Web Accessibility and SEO

What is the value of finding content if the user experience and accessibility of that content is poor?

Does it matter how accessible content is, if nobody ever finds it?

Web accessibility and search engine optimization (SEO) are both about getting relevant content to users. Accessible content and search engine optimized content are both machine readable. Search engines and assistive technologies (such as screen readers) are quite similar. In many ways, search engines are deaf, blind, use only a keyboard, and have limited technical abilities. Both rely on content structure, semantics, and functionality to either present content to users or determine the relevance of content.

Accessibility and SEO Magic

SEO has always had an element of what I call “voodoo magic”. It involves guessing or deducing what algorithms a search engine might use to determine the relevance of certain content, then implementing content strategies that best utilize those supposed algorithms. Fortunately, web accessibility has more straightforward guidelines – though a fair amount of voodoo magic is still required to get content to actually work correctly across browsers and assistive technologies. Occasionally the recommendations of SEO “experts” and accessibility “experts” have been at odds; implementing a tactic for SEO would be detrimental to accessibility, or vice versa.

In the 10 years I have been working in the web accessibility field, I have seen SEO and accessibility align more closely. There is now significant overlap between these two fields. Interestingly, SEO has lost most of its “black hat” techniques and has evolved to align more with accessibility, which has changed very little. This, I suppose, provides some validation to long-standing accessibility principles and their intent on making the web a better place for everyone.

Keyword stuffing – using keywords in portions of the page that would not typically be noticed by most users (such as alternative text or title attributes values), but that would be identified by search engines – is a good example of “black hat” SEO. This ‘hidden’ content often isn’t – it may be read or made available to users with disabilities resulting in confusion and poor accessibility. Fortunately, search engines have progressed and now penalize such tactics. SEO, like accessibility, now advocates proper, descriptive alternative text and advisory title attributes that are accurately descriptive of their related content. These are used by search engines to help determine the content of images.

SEO and Accessibility Alignment

The list of accessibility and SEO practices that are closely in alignment include:

• Using proper alternative text for images
• Providing a clear and proper heading structure and avoiding empty headings
• Providing descriptive link text (i.e., avoiding “click here”)
• Ensuring page titles are descriptive, yet succinct
• Not relying on JavaScript for things that don’t need it
• Avoiding mouse dependent interaction
• Using standard web formats when possible
• Providing transcripts and captions for video
• Identifying the language of pages and page content
• Allowing multiple ways of finding content (e.g., search, a site map, table of contents, clear navigation, etc.)
• Using text instead of images when possible
• Providing useful links to related and relevant resources
• Ensuring URLs are human readable and logical
• Presenting a clear and consistent navigation and page structure
• Avoiding CSS and other stylistic markup to present content or meaning
• Defining abbreviations and acronyms

Of course content is king, in both accessibility and SEO.

HTML5, Accessibility, and SEO

HTML5 provides the following improved semantics that will increase both accessibility and search engine accuracy:

• <figure> and <figcaption> for associating images and descriptive text.
• <nav>, <header>, <footer>, <article>, and <aside> for better identifying significant page areas. ARIA provides even enhanced functionality here (especially in the notably missing identification of page main content).
• <details> and <summary> for associating related content.
• Associated <track> elements with <audio> and <video>.
• Microformats, RDFa, microelements, <time> and many similar features can provide useful metadata and functionality.

I believe that HTML5 will further bring SEO and web accessibility into alignment.

Off-screen Content

SEO advocates often have concern over the accessibility technique of using CSS to hide content off-screen. This technique allows useful content to be presented to screen reader users. This should, of course, be used sparingly and only in cases where the content makes sense visually, but additional content may be necessary for users that cannot see the visual presentation. While keyword stuffing in hidden content was once part of the “voodoo magic” of SEO, it is now verboten. Search engines can inflict harsh ranking punishments on pages that are found to be using deceptive or malicious tactics.

Despite these concerns, rest assured that the proper use of off-screen content will not impact search engine rankings. We have received confirmation (unofficial, of course) from Google that such practices are perfectly acceptable, so long as they are not deceptive or malicious. Perhaps the strongest indication that this is true is that the first link on the Google.com homepage is hidden using the off-screen technique WebAIM has always advocated.

SEO + Accessibility = Win!

There is much evidence that suggests that accessibility not only supports high search engine rankings, but that Google may actually favor pages that have strong implementations of accessibility. This is, of course, difficult to prove. I do know that the WebAIM site, which we have tried to keep highly accessible, has certainly been highly favored in search engines for accessibility related terms despite implementing very few SEO-specific techniques.

Good accessibility and good search engine optimization is a great combination for content authors and end users.