Accessibility for search engines
A few checkpoints for accessibility
Having seen why high accessibility overlaps with effective search-engine optimization, let's see how it does so. Let's touch upon each Priority 1 checkpoint in the W3C Web Content Accessibility Guidelines which affects search-engine optimization.
1.1 Provide a text equivalent for every non-text element (e.g., via “alt”, “longdesc”, or in element content)...
Not only are search engines unable to understand image and movie files, they also cannot interpret any textual content that is based on vision. alt and longdesc attributes therefore help them understand the subject of any such content.
Search engines are also deaf in reference to audio files. Again, providing textual descriptions to these files allows search engines to better interpret and rank the content that they cannot hear.
1.2 Provide redundant text links for each active region of a server-side image map.
Text links are very important to search engines, since anchor text labels the content of a link’s target page. In fact, many search engine optimizers consider anchor text to be the single most important factor in modern search algorithms. If a website uses an image map rather than a text-based menu as the primary navigational method, a redundant text-only menu elsewhere on the page will give search engines additional information about the content of each target page.
4.1 Clearly identify changes in the natural language of a document’s text and any text equivalents (e.g., captions).
Major search engines maintain country and language-specific indexes. Specifying the language of a document or of text within a document, helps search engines decide in which indexes to place it.
6.3 Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported [...]
14.1 Use the clearest and simplest language appropriate for a site’s content.
It is a bit less obvious how this particular checkpoint aids search-engine optimization. If a website contains the clearest and simplest language appropriate for the site’s content, it is probably using those keywords with which potential searchers will be most familiar. Searchers tend to use succinct queries containing familiar language. Thus, to receive maximum traffic from search engines, it is best that a website contain the same words which the site’s audience will use when searching.
The benefits do not end with Priority 1 — many of the Priority 2 and 3 Checkpoints are important for search-engine optimization purposes, too. For instance, Checkpoints 6.2 and 6.5 refer to the accessibility of dynamic content. In fact, making dynamic content search engine-friendly is one of the most daunting tasks a search engine optimizer faces when working on an eCommerce or a database-driven site. Following the W3C’s recommendations can help to avoid any indexing or ranking problems related to using dynamic content.
From the horse’s mouth
If you doubt any of the above, perhaps a visit to Google’s Webmaster Guidelines could convince you that Google rewards high accessibility. This page specifically mentions best practices which will help Google “find, index, and rank your site.”
DESIGN AND CONTENT GUIDELINES:
- Make a site with a clear hierarchy and text links. Every page should be reachable from at least one static text link.
- Offer a site map to your users with links that point to the important parts of your site. If the site map is larger than 100 or so links, you may want to break the site map into separate pages.
- Create a useful, information-rich site, and write pages that clearly and accurately describe your content.
- Think about the words users would type to find your pages, and make sure that your site actually includes those words within it.
- Try to use text instead of images to display important names, content, or links. The Google crawler doesn’t recognize text contained in images.
- Make sure that your title and alt tags are descriptive and accurate. [...]
Note that each of Google’s guidelines actually correlates with a W3C Web Content Accessibility Guideline. Oddly enough, the word “accessibility” does not actually appear in Google’s Webmaster Guidelines. Perhaps they are afraid of scaring off some webmasters with technical jargon? In any case, it is clear that Google is lobbying for high accessibility.
Another feather in accessibility’s cap
The checkpoints highlighted above are just a few of the many ways that high accessibility helps optimize a website for search engines — many of the other checkpoints in the W3C Web Content Accessibility Guidelines are helpful for search-engine optimization as well. If accessibility gets a website more traffic from Google, even better!
The good news is that a web designer who follows best practices for accessibility is already practicing solid white hat search-engine optimization. Search engines need not scare anyone. When in doubt, design your site to be accessible to blind and deaf users as well as those who view websites via text-only browsers, and search-engine optimization will fall into place automatically.