Friday, December 26, 2008

Potential problems | Search Engine Optimization

Requesting reconsideration

Watch a video on why your site may not be appearing in search results and how to get it reconsidered.

If your site isn't appearing in Google search results, or it's performing more poorly than it once did (and you believe that it does not violate our webmaster guidelines), you can ask Google to reconsider your site.

In addition, if you recently purchased a domain that you think may have violated our guidelines before you owned it, you can use the reconsideration request form to let us know that you recently acquired the site and that it now adheres to the guidelines.

To request reconsideration of your site:

1. First, make sure you've added your site to your Webmaster Tools account, and verified site ownership.
2. Sign in to Google Webmaster Tools.
3. On the Dashboard, under Talk to Google in the list on the right, click Request reconsideration and follow the steps.




Hidden text and links

Hiding text or links in your content can cause your site to be perceived as untrustworthy since it presents information to search engines differently than to visitors. Text (such as excessive keywords) can be hidden in several ways, including:

* Using white text on a white background
* Including text behind an image
* Using CSS to hide text
* Setting the font size to 0

Hidden links are links that are intended to be crawled by Googlebot, but are unreadable to humans because:

* The link consists of hidden text (for example, the text color and background color are identical).
* CSS has been used to make tiny hyperlinks, as little as one pixel high.
* The link is hidden in a small character - for example, a hyphen in the middle of a paragraph.

If your site is perceived to contain hidden text and links that are deceptive in intent, your site may be removed from the Google index, and will not appear in search results pages. When evaluating your site to see if it includes hidden text or links, look for anything that's not easily viewable by visitors of your site. Are any text or links there solely for search engines rather than visitors?

If you're using text to try to describe something search engines can't access - for example, Javascript, images, or Flash files - remember that many human visitors using screen readers, mobile browsers, browsers without plug-ins, and slow connections will not be able to view that content either. Using descriptive text for these items will improve the accessibility of your site. You can test accessibility by turning off Javascript, Flash, and images in your browser, or by using a text-only browser such as Lynx. Some tips on making your site accessible include:

* Images: Use the alt attribute to provide descriptive text. In addition, we recommend using a human-readable caption and descriptive text around the image.
* Javascript: Place the same content from the Javascript in a no script tag. If you use this method, ensure the contents are exactly same as what is contained in the Javascript and that this content is shown to visitors who do not have Javascript enabled in their browser.
* Videos: Include descriptive text about the video in HTML. You might also consider providing transcripts.

If you do find hidden text or links on your site, either remove them or, if they are relevant for your site's visitors, make them easily viewable. If your site has been removed from our search results, review our webmaster guidelines for more information. Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.



Site removed from the Google index

Google may temporarily or permanently remove sites from its index and search results if it believes it is obligated to do so by law, if the sites do not meet Google's quality guidelines, or for other reasons, such as if the sites detract from users' ability to locate relevant information. We cannot comment on the individual reasons a page may be removed. However, certain actions such as cloaking, writing text in such a way that it can be seen by search engines but not by users, or setting up pages/links with the sole purpose of fooling search engines may result in removal from our index. Please read our Webmaster Guidelines for more information.

If your site is blocked from our index because it violates our quality guidelines, we may alert you about this using our Webmaster Tools. Simply sign in to our Webmaster Tools, add your site URL, and verify site ownership. The Overview page provides information about the indexing of your site.

If you receive a notification that your site violates our quality guidelines, you can modify your site so that it meets these guidelines, then submit your site for reconsideration.








Cloaking, sneaky Javascript redirects, and doorway pages
Cloaking

Cloaking refers to the practice of presenting different content or URLs to users and search engines. Serving up different results based on user agent may cause your site to be perceived as deceptive and removed from the Google index.

Some examples of cloaking include:

* Serving a page of HTML text to search engines, while showing a page of images or Flash to users.
* Serving different content to search engines than to users.

If your site contains elements that aren't crawlable by search engines (such as rich media files other than Flash, JavaScript, or images), you shouldn't provide cloaked content to search engines. Rather, you should consider visitors to your site who are unable to view these elements as well. For instance:

* Provide alt text that describes images for visitors with screen readers or images turned off in their browsers.
* Provide the textual contents of JavaScript in a noscript tag.

Ensure that you provide the same content in both elements (for instance, provide the same text in the JavaScript as in the noscript tag). Including substantially different content in the alternate element may cause Google to take action on the site.
Sneaky JavaScript redirects

When Googlebot indexes a page containing JavaScript, it will index that page but it cannot follow or index any links hidden in the JavaScript itself. Use of JavaScript is an entirely legitimate web practice. However, use of JavaScript with the intent to deceive search engines is not. For instance, placing different text in JavaScript than in a noscript tag violates our webmaster guidelines because it displays different content for users (who see the JavaScript-based text) than for search engines (which see the noscript-based text). Along those lines, it violates the webmaster guidelines to embed a link in JavaScript that redirects the user to a different page with the intent to show the user a different page than the search engine sees. When a redirect link is embedded in JavaScript, the search engine indexes the original page rather than following the link, whereas users are taken to the redirect target. Like cloaking, this practice is deceptive because it displays different content to users and to Googlebot, and can take a visitor somewhere other than where they intended to go.

Note that placement of links within JavaScript is alone not deceptive. When examining JavaScript on your site to ensure your site adheres to our guidelines, consider the intent.

Keep in mind that since search engines generally can't access the contents of JavaScript, legitimate links within JavaScript will likely be inaccessible to them (as well as to visitors without Javascript-enabled browsers). You might instead keep links outside of JavaScript or replicate them in a noscript tag.
Doorway pages

Doorway pages are typically large sets of poor-quality pages where each page is optimized for a specific keyword or phrase. In many cases, doorway pages are written to rank for a particular phrase and then funnel users to a single destination.

Whether deployed across many domains or established within one domain, doorway pages tend to frustrate users, and are in violation of our webmaster guidelines.

Google's aim is to give our users the most valuable and relevant search results. Therefore, we frown on practices that are designed to manipulate search engines and deceive users by directing them to sites other than the ones they selected, and that provide content solely for the benefit of search engines. Google may take action on doorway sites and other sites making use of these deceptive practice, including removing these sites from the Google index.

If your site has been removed from our search results, review our webmaster guidelines for more information. Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.










Duplicate content

Duplicate content generally refers to substantive blocks of content within or across domains that either completely match other content or are appreciably similar. Mostly, this is not deceptive in origin. Examples of non-malicious duplicate content could include:

* Discussion forums that can generate both regular and stripped-down pages targeted at mobile devices
* Store items shown or linked via multiple distinct URLs
* Printer-only versions of web pages

However, in some cases, content is deliberately duplicated across domains in an attempt to manipulate search engine rankings or win more traffic. Deceptive practices like this can result in a poor user experience, when a visitor sees substantially the same content repeated within a set of search results.

Google tries hard to index and show pages with distinct information. This filtering means, for instance, that if your site has a "regular" and "printer" version of each article, and neither of these is blocked in robots.txt or with a noindex meta tag, we'll choose one of them to list. In the rare cases in which Google perceives that duplicate content may be shown with intent to manipulate our rankings and deceive our users, we'll also make appropriate adjustments in the indexing and ranking of the sites involved. As a result, the ranking of the site may suffer, or the site might be removed entirely from the Google index, in which case it will no longer appear in search results.

There are some steps you can take to proactively address duplicate content issues, and ensure that visitors see the content you want them to.

* Consider blocking pages from indexing: Rather than letting Google's algorithms determine the "best" version of a document, you may wish to help guide us to your preferred version. For instance, if you don't want us to index the printer versions of your site's articles, disallow those directories or make use of regular expressions in your robots.txt file.
* Use 301s: If you've restructured your site, use 301 redirects ("RedirectPermanent") in your .htaccess file to smartly redirect users, Googlebot, and other spiders. (In Apache, you can do this with an .htaccess file; in IIS, you can do this through the administrative console.)
* Be consistent: Try to keep your internal linking consistent. For example, don't link to http://www.example.com/page/ and http://www.example.com/page and http://www.example.com/page/index.htm.
* Use top-level domains: To help us serve the most appropriate version of a document, use top-level domains whenever possible to handle country-specific content. We're more likely to know that www.example.de contains Germany-focused content, for instance, than www.example.com/de or de.example.com.
* Syndicate carefully: If you syndicate your content on other sites, Google will always show the version we think is most appropriate for users in each given search, which may or may not be the version you'd prefer. However, it is helpful to ensure that each site on which your content is syndicated includes a link back to your original article. You can also ask those who use your syndicated material to block the version on their sites with robots.txt.
* Use Webmaster Tools to tell us how you prefer your site to be indexed: You can tell Google your preferred domain (for example, www.example.com or http://example.com).
* Minimize boilerplate repetition: For instance, instead of including lengthy copyright text on the bottom of every page, include a very brief summary and then link to a page with more details.
* Avoid publishing stubs: Users don't like seeing "empty" pages, so avoid placeholders where possible. For example, don't publish pages for which you don't yet have real content. If you do create placeholder pages, use robots.txt to block these from being crawled.
* Understand your content management system: Make sure you're familiar with how content is displayed on your web site. Blogs, forums, and related systems often show the same content in multiple formats. For example, a blog entry may appear on the home page of a blog, in an archive page, and in a page of other entries with the same label.
* Minimize similar content: If you have many pages that are similar, consider expanding each page or consolidating the pages into one. For instance, if you have a travel site with separate pages for two cities, but the same information on both pages, you could either merge the pages into one page about both cities or you could expand each page to contain unique content about each city.

Duplicate content on a site is not grounds for action on that site unless it appears that the intent of the duplicate content is to be deceptive and manipulate search engine results. If your site suffers from duplicate content issues, and you don't follow the advice listed above, we do a good job of choosing a version of the content to show in our search results.

However, if our review indicated that you engaged in deceptive practices and your site has been removed from our search results, review your site carefully. If your site has been removed from our search results, review our webmaster guidelines for more information. Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.

If you find that another site is duplicating your content by scraping (misappropriating and republishing) it, it's unlikely that this will negatively impact your site's ranking in Google search results pages. If you do spot a case that's particularly frustrating, you are welcome to file a DMCA request to claim ownership of the content and request removal of the other site from Google's index.







Keyword stuffing

"Keyword stuffing" refers to the practice of loading a webpage with keywords in an attempt to manipulate a site's ranking in Google's search results. Filling pages with keywords results in a negative user experience, and can harm your site's ranking. Focus on creating useful, information-rich content that uses keywords appropriately and in context.

To fix this problem, review your site for misused keywords. Typically, these will be lists or paragraphs of keywords, often randomly repeated. Check carefully, because keywords can often be in the form of hidden text, or they can be hidden in title tags or alt attributes.

Once you've made your changes and are confident that your site no longer violates our webmaster guidelines, submit your site for reconsideration.







Little or no original content

One of the most important steps in improving your site's ranking in Google search results is to ensure that it contains plenty of rich information that includes relevant keywords, used appropriately, that indicate the subject matter of your content.

However, some webmasters attempt to improve their page's ranking and attract visitors by creating pages with many words but little or no authentic content. Google will take action against domains that try to rank more highly by just showing scraped or other auto-generated pages that don't add any value to users. Examples include:

* Thin affiliate sites: These sites collect pay-per-click (PPC) revenue by sending visitors to the sites of affiliate programs, while providing little or no value-added content or service to the user. These sites usually have no original content and may be cookie-cutter sites or templates with no unique content.
* Doorway pages: Pages created just for search engines
* Auto-generated content: Content generated programatically. Often this will consist of random paragraphs of text that make no sense to the reader but that may contain search keywords.
* Scraped content: Some webmasters make use of content taken from other, more reputable sites on the assumption that increasing the volume of web pages with random, irrelevant content is a good long-term strategy. Purely scraped content, even from high-quality sources, may not provide any added value to your users without additional useful services or content provided by your site. It's worthwhile to take the time to create original content that sets your site apart. This will keep your visitors coming back and will provide useful search results.

There is no problem in being an affiliate as long as you create some added value for your users and produce valuable content that gives a user a reason to visit your site. For example, you could create product reviews, ratings, and product comparisons.

If your site has been removed from our search results, review our webmaster guidelines for more information. Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.







Link schemes

Your site's ranking in Google search results is partly based on analysis of those sites that link to you. The quantity, quality, and relevance of links count towards your rating. The sites that link to you can provide context about the subject matter of your site, and can indicate its quality and popularity. However, some webmasters engage in link exchange schemes and build partner pages exclusively for the sake of cross-linking, disregarding the quality of the links, the sources, and the long-term impact it will have on their sites. This is in violation of Google's webmaster guidelines and can negatively impact your site's ranking in search results. Examples of link schemes can include:

* Links intended to manipulate PageRank
* Links to web spammers or bad neighborhoods on the web
* Excessive reciprocal links or excessive link exchanging ("Link to me and I'll link to you.")
* Buying or selling links that pass PageRank

The best way to get other sites to create relevant links to yours is to create unique, relevant content that can quickly gain popularity in the Internet community. The more useful content you have, the greater the chances someone else will find that content valuable to their readers and link to it. Before making any single decision, you should ask yourself the question: Is this going to be beneficial for my page's visitors?

It is not only the number of links you have pointing to your site that matters, but also the quality and relevance of those links. Creating good content pays off: Links are usually editorial votes given by choice, and the buzzing blogger community can be an excellent place to generate interest.

Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.






Automated queries

Google's Terms of Service do not allow the sending of automated queries of any sort to our system without express permission in advance from Google. Sending automated queries absorbs resources and includes using any software (such as WebPosition Gold™) to send automated queries to Google to determine how a website or webpage ranks in Google search results for various queries.





Parked domains

A parked domain is a placeholder page for a domain that is not yet developed into a website. Often this is entirely legitimate - for example, a webmaster may put up an "Under construction" while the site itself is being built.

However, some webmasters register domains and park them in order to monetize those pages. Typically this is done by filling the pages with ads in the hope of gaining pay-per-click (PPC) revenue.

These parked pages don't provide value to searchers, so we don't typically return them in our search results. If you have parked domains, activate the domains and fill them with useful content to make them eligible for being indexed and returned in search results.

If your site has been removed from our search results, review our webmaster guidelines for more information. Once you've made your changes and are confident that your site no longer violates our guidelines, submit your site for reconsideration.

More information for publishers | Search Engine Optimization

Developing mobile sites

We believe the mobile web is becoming increasingly important, but it's not always easy to know where to start. So, we've put together this page of tools available for developers of mobile content, to help ease the way.
Mobile markup

Mobile web pages come in several markup dialects, including WML, XHTML Basic, XHTML MP and cHTML. WML is an older standard that is supported by many browsers, and still widely used in some markets. cHTML is used primarily in Japan, but also some parts of Europe. XHTML Basic and XHTML MP are almost identical subsets of HTML, used globally, but particularly in North America and Europe. XHTML dialects are the newest and most expressive of markups, and are gaining usage. XHTML Basic 1.1 and XHTML MP 1.2 are a good choice for new development, but your choice will vary according to your target market.
Validation

Valid pages are likely to render correctly on more mobile devices.

Published mobile markup standards include:

* XHTML Basic 1.1
* XHTML MP 1.2
* cHTML
* WML 1.3

Validators include the following:

* Mobile-friendly XHTML Validator (W3C)
* Mobile-readiness checker (.mobi)
* mobileOK Basic Checker (TAW)
* WuRML (shadowplay.net)

Emulation

You may be confident that your page is valid XHTML or valid WML, but are you certain that it's going to look right on a real phone screen? Use an emulator to test your page, and avoid the hassle of buying them all.

* Phone Simulator (Openwave)
* Mobile emulator (.mobi)
* i-mode emulator (DoCoMo)
* User-Agent Switcher (Firefox plug-in)
* wmlbrowser (Firefox plug-in)
* XHTML Mobile Profile (Firefox plug-in)

Google resources

* About mobile sites and the Google index
* Best practices for mobile developers

Other resources

* W3C Mobile Web Best Practices
* .mobi Switch On! Guides
* The Wireless FAQ
* mobileOK Basic Tests
* WURFL (Wireless Universal Resource File)





First Click Free

If you offer subscription-based access to your website content, or if users must register to access your content, then search engines cannot access some of your site's most relevant, valuable content.

Implementing Google's First Click Free (FCF) for your content allows you to include your restricted content in Google's main search index. Our intention is to protect your content while allowing for its inclusion in Google's search index. First Click Free has two main goals:

* To include high-quality content in Google's search index, providing a better experience for Google users who may not have known that content existed.
* To provide a promotion and discovery opportunity for webmasters of sites with restricted content.

To implement First Click Free, you need to allow all users who find a document on your site via Google search to see the full text of that document, even if they have not registered or subscribed to see that content. The user's first click to your content area is free. However, once that user clicks a link on the original page, you can require them to sign in or register to read further.

In order to successfully crawl your site, Google needs to be able to crawl your content without filling out a registration form. The easiest way to do this is to configure your webservers not to serve the registration page to our crawlers (when the User-Agent is "Googlebot") so that Googlebot can crawl these pages successfully. You can choose to allow Googlebot access to some restricted pages but not others. More information about technical requirements.




Friend Connect

Note: Google Friend Connect is currently a beta release and will be available only to a limited number of site owners. To find out more, please visit http://www.google.com/friendconnect/.

Google Friend Connect lets you grow traffic by easily adding social features to your website and makes it more engaging for your visitors. By copying a snippet of code, you can equip your site with social features, enabling your visitors to log in with existing credentials and see who among their friends is already registered at that site. It also gives them one-click access to invite friends from their existing friends lists on other sites, such as Facebook or orkut.

With Google Friend Connect, you can make your site more engaging with social applications created by Google and the Open Social developer community. By adding rich, relevant, and interactive gadgets to your site, visitors will interact more actively with content on your site and spend more time on your site.

Enabling Friend Connect on your site won't impact your site's rankings in Google's search results.

Browser compatibility | Site design and content

Browser compatibility

Users typically view your website using a browser. Each browser interprets your website code in a slightly different manner, which means that it may appear differently to visitors using different browsers. In general, you should avoid relying on browser specific behavior, such as relying on a browser to correctly detect a content-type or encoding when you did not specify one. In addition, there are some steps you can take to make sure your site doesn't behave in unexpected ways.
Test your site in as many browsers as possible

Once you've created your web design, you should review your site's appearance and functionality on multiple browsers to make sure that all your visitors are getting the experience you worked so hard to design. Ideally, you should start testing as early in your site development process as possible. Different browsers - and even different versions of the same browser - can see your site differently. You can use services such as Google Analytics to get a good idea of the most popular browsers used to view your site.
Write good, clean HTML

While your site may appear correctly in some browsers even if your HTML is not valid, there's no guarantee that it will appear correctly in all browsers - or in all future browsers. The best way to make sure that your page looks the same in all browsers is to write your page using valid HTML and CSS, and then test it in as many browsers as possible. Clean, valid HTML is a good insurance policy, and using CSS separates presentation from content, and can help pages render and load faster. Validation tools, such as the free online HTML and CSS validators provided by the W3 Consortium, are useful for checking your site, and tools such as HTML Tidy can help you quickly and easily clean up your code. (Although we do recommend using valid HTML, it's not likely to be a factor in how Google crawls and indexes your site.)
Specify your character encoding

To help browsers render the text on your page, you should always specify an encoding for your document. This encoding should appear at the top of the document (or frame) as some browsers won't recognize charset declarations that appear deep in the document. In addition, you should make sure that your web server is not sending conflicting HTTP headers. A header such as content-type: text/html; charset=ISO-8859-1 will override any charset declarations in your page.
Consider accessibility

Not all users may have JavaScript enabled in their browsers. In addition, technologies such as Flash and ActiveX may not render well (or at all) in every browser. We recommend following our guidelines for using Flash and other rich media, and testing your site in a text-only browser such as Lynx. As a bonus, providing text-only alternatives to rich-media content and functionality will make it easier for search engines to crawl and index your site, and also make your site more accessible to users who use alternative technologies such as screenreaders.

About rel="nofollow" | Site design and content

About rel="nofollow"

"Nofollow" provides a way for webmasters to tell search engines "Don't follow links on this page" or "Don't follow this specific link."

Originally, the nofollow attribute appeared in the page-level meta tag, and instructed search engines not to follow (i.e., crawl) any outgoing links on the page. For example:



Before nofollow was used on individual links, preventing robots from following individual links on a page required a great deal of effort (for example, redirecting the link to a URL blocked in robots.txt). That's why the nofollow attribute value of the rel attribute was created. This gives webmasters more granular control: instead of telling search engines and bots not to follow any links on the page, it lets you easily instruct robots not to crawl a specific link. For example:

sign in

How does Google handle nofollowed links?

We don't follow them. This means that Google does not transfer PageRank or anchor text across these links. Essentially, using nofollow causes us to drop the target links from our overall graph of the web. However, the target pages may still appear in our index if other sites link to them without using nofollow, or if the URLs are submitted to Google in a Sitemap. Also, it's important to note that other search engines may handle nofollow in slightly different ways.

What are Google's policies and some specific examples of nofollow usage?

Here are some cases in which you might want to consider using nofollow:

* Untrusted content: If you can't or don't want to vouch for the content of pages you link to from your site — for example, untrusted user comments or guestbook entries — you should nofollow those links. This can discourage spammers from targeting your site, and will help keep your site from inadvertently passing PageRank to bad neighborhoods on the web. In particular, comment spammers may decide not to target a specific content management system or blog service if they can see that untrusted links in that service are nofollowed. If you want to recognize and reward trustworthy contributors, you could decide to automatically or manually remove the nofollow attribute on links posted by members or users who have consistently made high-quality contributions over time.
* Paid links: A site's ranking in Google search results is partly based on analysis of those sites that link to it. In order to prevent paid links from influencing search results and negatively impacting users, we urge webmasters use nofollow on such links. Search engine guidelines require machine-readable disclosure of paid links in the same way that consumers online and offline appreciate disclosure of paid relationships (for example, a full-page newspaper ad may be headed by the word "Advertisement"). More information on Google's stance on paid links.
* Crawl prioritization: Search engine robots can't sign in or register as a member on your forum, so there's no reason to invite Googlebot to follow "register here" or "sign in" links. Using nofollow on these links enables Googlebot to crawl other pages you'd prefer to see in Google's index. However, a solid information architecture — intuitive navigation, user- and search-engine-friendly URLs, and so on — is likely to be a far more productive use of resources than focusing on crawl prioritization via nofollowed links.

Meta tags | Site design and content

Meta tags

Meta tags are a great way for webmasters to provide search engines with information about their sites. Meta tags can be used to provide information to all sorts of clients, and each system processes only the meta tags they understand and ignores the rest. Meta tags are added to the section of your HTML page and generally look like this:

"http://www.w3.org/TR/html4/loose.dtd">











Example Books - high-quality used books for children



Google understands the following meta tags (and related items):
This tag provides a short description of the page. In some situations this description is used as a part of the snippet shown in the search results. More information
The Title of the Page While technically not a meta tag, this tag is often used together with the "description". The contents of this tag are generally shown as the title in search results (and of course in the user's browser). More information

These meta tags can control the behavior of search engine crawling and indexing. The robots meta tag applies to all search engines, while the "googlebot" meta tag is specific to Google. The default values are "index, follow" (the same as "all") and do not need to be specified. We understand the following values (when specifying multiple values, separate them with a comma):

* noindex: prevents the page from being indexed
* nofollow: prevents the Googlebot from following links from this page
* nosnippet: prevents a snippet from being shown in the search results
* noodp: prevents the alternative description from the ODP/DMOZ from being used
* noarchive: prevents Google from showing the Cached link for a page.
* unavailable_after:[date]: lets you specify the exact time and date you want to stop crawling and indexing of this page
* noimageindex: lets you specify that you do not want your page to appear as the referring page for an image that appears in Google search results.

As a side-note, you can now also specify this information in the header of your pages using the "X-Robots-Tag" HTTP header directive. This is particularly useful if you wish to fine-tune crawling and indexing of non-HTML files like graphics or other kinds of documents.
When we recognize that the contents of a page are not in the language that the user is likely to want to read, we often provide a link to a translation in the search results. In general, this gives you the chance to provide your unique and compelling content to a much larger group of users. However, there may be situations where this is not desired. This meta tag tells Google that you don't want us to provide a translation for this page. More information
You can use this tag on the top-level page of your site to verify ownership for Webmaster Tools. Please note that while the values of the "name" and "content" attributes must match exactly what is provided to you (including upper and lower case), it doesn't matter if you change the tag from XHTML to HTML or if the format of the tag matches the format of your page. More information
This meta tag defines the page's content type and character set. Make sure that you surround the value of the content attribute with quotes - otherwise the charset attribute may be interpreted incorrectly. More information
This meta tag sends the user to a new URL after a certain amount of time, and is sometimes used as a simple form of redirection. However, it is not supported by all browsers and can be confusing to the user. The W3C recommends that this tag not be used. We recommend using a server-side 301 redirect instead.

Other points to note:

* Google can read both HTML and XHTML-style meta tags, regardless of the code used on the page.
* With the exception of "verify", case is generally not important in meta tags.

This is not an exclusive list of available meta tags, and you should feel free to use unlisted meta tags if they are important to your site. Just remember that Google will ignore meta tags it doesn't know.

Flash and other rich media files | Site design and content

Flash and other rich media files
Flash Learn more...
Silverlight Learn more...
Video Learn more...
iFrames Learn more...
Best practices Learn more...

Google can index most types of pages and files (detailed list).
In general, however, search engines are text based. This means that in order to be crawled and indexed, your content needs to be in text format. (Google can now index text content contained in Flash files, but other search engines may not.)

This doesn't mean that you can't include rich media content such as Flash, Silverlight, or videos on your site; it just means that any content you embed in these files should also be available in text format or it won't be accessible to search engines. The examples below focus on the most common types of non-text content, but the guidelines are similar for any other types: Provide text equivalents for all non-text files.

This will not only increase Googlebot's ability to successfully crawl and index your content; it will also make your content more accessible. Many people, for example users with visual impairments, who use screen readers, or have low bandwidth connections, cannot see images on web pages, and providing text equivalents widens your audience.
Flash
back to top

Google can now discover and index text content in SWF files of all kinds, including self-contained Flash websites and Flash gadgets such as buttons or menus. This includes all textual content visible to the user. In addition, we can now find and follow URLs embedded in Flash files. We'll crawl and index this content in the same way that we crawl and index other content on your site - webmasters don't need to take any special action. However, we don't guarantee that we'll crawl or index all the content, Flash or otherwise.

We're continually working to improve our indexing of Flash files, but there are some limitations:

* Googlebot does not execute some types of JavaScript. If your webpage uses JavaScript to load a Flash file, we may not be able to discover and index the contents of that file.
* We currently do not attach content from external resources that are loaded by your Flash files. If your Flash file loads another file - such as an HTML file, an XML file, or another SWF file - we may index the contents of those files, but we won't consider that content to be part of the content in your Flash files.
* We're currently unable to index the bidirectional language content (for example, Hebrew or Arabic) in Flash files.

Note that while Google can index the content of Flash files, other search engines may not be able to. Providing text equivalents of these files will help other search engines crawl and index your content.

You could also consider using sIFR (Scalable Inman Flash Replacement). sIFR (an open-source project) lets webmasters replace text elements with Flash equivalents. Using this technique, content and navigation is displayed by an embedded Flash object but, because the content is contained in the HTML source, it can be read by non-Flash users (including search engines).
Silverlight and other rich media formats
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Google can crawl and index the text content of Flash files, but we still have problems accessing the content of other rich media formats such as Silverlight. These rich media formats are is inherently visual, which can cause some problems for Googlebot. Unlike some Internet spiders, Googlebot can read some rich media files and extract the text and links in them, but the structure and context are missing. Also, rich media designers often include content in the form of graphics, and because Google can't detect words included in graphics, it can miss important keywords. In other words, even if we can crawl your content and it is in our index, it might be missing some text, content, or links.
Video
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Googlebot cannot crawl the content of video files, so it's important that you provide information about videos you include. Consider creating a transcript of the video you want to include, or provide a detailed description of the video inside your HTML. If you have video content, you can host it on Google Video, YouTube, or a number of other video hosting providers. Searchers can view Google Video or YouTube videos directly from the Google search results page.
IFrames
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IFrames are sometimes used to display content on web pages. Content displayed via iFrames may not be indexed and available to appear in Google's search results. We recommend that you avoid the use of iFrames to display content. If you do include iFrames, make sure to provide additional text-based links to the content they display, so that Googlebot can crawl and index this content.
Best practices
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If you do plan to use rich media on your site, here are some recommendations that can help prevent problems.

* Try to use rich media only where it is needed. We recommend that you use HTML for content and navigation. This makes your site more Google-friendly, and also makes it accessible to a larger audience including, for example, readers with visual impairments that require the use of screen readers, users of old or non-standard browsers, and users with limited or low-bandwidth connections such as a cellphone or mobile device. An added bonus? Using HTML for navigation will allow users to bookmark content and send direct links in email.
* Provide text versions of pages. Silverlight is often used as a splash screen on the home page, where the root URL of a website has a rich media intro that links to HTML content deeper into the site. If you use this approach on your website, make sure there is a regular HTML link on that front page to a text-based page where a user (or Googlebot) can navigate throughout your site without the need for rich media.
* Consider using robots.txt to block rich media files. If you're providing text versions of content, you may want to consider using robots.txt to block access to the rich media versions.

Images | Site design and content

Images

Watch a video on using images on your site.

When publishing images on the web, all our usual webmaster guidelines apply.

Because images are often copied by users, Google often finds multiple copies of the same image online. We use many different signals to identify the original source of the image, and you can help by providing us with as much information as you can. In addition, the information you give about an image tells us about its content and subject matter.

Don't embed text inside images - search engines generally won't be able to read it.
Tell us as much as you can about the image
Give your images detailed, informative filenames

The filename can give Google clues about the subject matter of the image. Try to make your filename a good description of the subject matter of the image. For example, my-new-black-kitten.jpg is a lot more informative than IMG00023.JPG. Descriptive filenames can also be useful to users: If we're unable to find suitable text in the page on which we found the image, we'll use the filename as the image's snippet in our search results.
Create great alt text

The alt attribute is used to describe the contents of an image file. It's important for several reasons:

* It provides Google with useful information about the subject matter of the image. We use this information to help determine the best image to return for a user's query.
* Many people—for example, users with visual impairments, or people using screen readers or who have low-bandwidth connections—may not be able to see images on web pages. Descriptive alt text provides these users with important information.

Not so good:



Better:

puppy

Best:

Dalmatian puppy playing fetch

To be avoided

puppy dog baby <br />dog pup pups puppies doggies pups litter puppies dog retriever <br /> labrador wolfhound setter pointer puppy jack russell terrier <br />puppies dog food cheap dogfood puppy food

Filling alt attributes with keywords ("keyword stuffing") results in a negative user experience, and may cause your site to be perceived as spam. Instead, focus on creating useful, information-rich content that uses keywords appropriately and in context. We recommend testing your content by using a text-only browser such as Lynx.
Anchor text

External anchor text (the text pages use to link to your site) reflects how other people view your pages. While typically webmasters can't control how other sites link to theirs, you can make sure that anchor text you use within your own site is useful, descriptive, and relevant. This improves the user experience and helps the user understand the link's destination. For example, you might link to a page of vacation photos like this: Photos of our June 2008 trip to Ireland.
Provide good context for your image

The page the image is on, and the content around the image (including any captions or image titles), provide search engines with important information about the subject matter of your image. For example, if you have a picture of a polar bear on a page about home-grown tomatoes, you'll be sending a confused message to the search engines about the subject matter of polarbear.jpg.

Wherever possible, it's a good idea to make sure that images are placed near the relevant text. In addition, we recommend providing good, descriptive titles and captions for your images.
Create a great user experience

* Good-quality photos appeal to users more than blurry, unclear images. In addition, other webmasters are much more likely to link to a good-quality image, which can increase visits to your site. Crisp, sharp images will also appear better in the thumbnail versions we display in our search results, and may therefore be more likely to be clicked on by users.
* Even if your image appears on several pages on your site, consider creating a standalone landing page for each image, where you can gather all its related information. If you do this, be sure to provide unique information - such as descriptive titles and captions - on each page.
* Not all users scroll to the bottom of a page, so consider putting your images high up on the page where it can be immediately seen.
* Think about whether you want people to share your images. If you prevent users from linking to images on your site, you'll prevent people from using your bandwidth, but you are also limiting the potential audience for your images and reducing their discoverability by search engines. Similarly, some people add copyright text or other information to their images. This won't impact your image's performance in search results, but again, you should think about the impact of this on your users.
* Consider structuring your directories so that similar images are saved together. For example, you might have one directory for thumbnails and another for full-size images; or you could create separate directories for each category of images (for example, you could create separate directories for Hawaii, Ghana, and Ireland under your Travel directory). If your site contains adult images, we recommend storing these in one or more directories separate from the rest of the images on your site.

With image search, just as with web search, our goal is to provide the best and most relevant search results to our users. Following the best practices listed above will increase the likelihood that your images will be returned in those search results.