Search engine optimisation and web accessibility

Web accessibility is just beginning to gain popularity among Internet marketing professionals. We're witnessing an industry that is gradually paying attention to the needs of wider and more diverse audiences.

By Carmen Mardiros

Web accessibility, as a concept, means that content on the Internet can be reached and read by all audiences.

The ultimate goal is to ensure that web content is universally accessible to all users, including people with disabilities. We have to think about anyone with poor eyesight, those who wear glasses, the colour blind, people affected by reading disorders and even 'silver surfers'.

The power of the search engines

It's difficult to tell whether search engines realise the sort of power and influence they have over the way the web evolves. It can be especially hard to determine whether search engines understand how they affect web page design from an accessibility standpoint.

It only takes them to favour one particular accessibility guideline and they will create a surge of interest among site owners for implementing that guideline.

Web accessibility organisations and individuals have tried hard over the years to promote the positive effects of accessible web design in the hope that it will become general practice. However, there's no more effective and easier way than through search engines.

The lure of search engine optimisation, promotion and marketing has become unstoppable. The addition of search engine algorithm factors and weights which match the accessibility guidelines will persuade site owners to make their websites more accessible - even if it is for mercenary reasons.

Popular search engines have the power to make the web a better place. In fact, it might be argued that the search engines companies have a moral responsibility towards all their customers and users. Accessible web sites are more likely to be good relevant results, not just relevant results, as an accessible site is open to all.

How to design accessible sites

However, even given the present search engine algorithms, it is possible to design sites that unites good search engine optimisation practices with accessibility for the visually impaired.

In our guide Search Engine Optimisation and Accessibility we have given an in depth analysis of SEO and accessibility.

In this article I will mention a few of the most important checkpoints for web site designers. The guide contains more checkpoints and a more in depth discussion of each and every one of them.

Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ASCII art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.

Ensure that dynamic content is accessible or provide an alternative presentation or page. Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation.

Until user agents render text equivalents for client-side image map links, provide redundant text links for each active region of a client-side image map.

Ensure that all information conveyed with colour is also interpretable without colour, for example from context or mark-up.

Ensure that foreground and background colour combinations provide sufficient contrast when viewed by someone having colour deficits or when viewed on a black and white screen.

Search engine optimisation techniques make good use of the separation of content and presentation. One approach that shows excellent results in search engine optimisation campaigns is the use of layouts controlled by Cascading Style Sheets (CSS). However, organize documents so they may be read without style sheets. For example, when an HTML document is rendered without associated style sheets, it must still be possible to read the document.

For data tables, identify row and column headers. For example, a table that lists UK tour businesses may have, as column header, "Tour operators". If this cell is not differentiated from others, then it is simply one phrase amongst many. However, if the cell is marked as a column header, this clearly communicates to search engines that this page is a resource about "Tour operators" and not just a page that mentions the phrase incidentally. As such, this makes it a powerful search engine promotion tool for describing structured data.

Provide summaries for tables. The CAPTION element and the "summary" attribute are intended to describe the purpose and content of a table. This is particularly useful when a table's content can only be properly understood visually rather than semantically.

Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page.

Frames are essentially deprecated and search engine promotion professionals will advise against their use for solid optimisation reasons. However, if frames must be used then the best available SEO strategy available is to enrich the frameset with descriptive content for search engines through the TITLE tag and the content of the NOFRAME element.

Do not to use link text such as "click here", "read more" or similar variants. Using anchor text, (sometimes called link text) to accurately and specifically describe the page to which it links is a cornerstone of effective search engine optimisation.

Provide information about the general layout of a site (e.g., a site map or table of contents).

Conclusion

It seems unlikely that all accessibility guidelines can or will be included in search engine algorithms. There is, however, a clear tendency that accessibility as a whole will be factored in more strongly in the near future, and some guidelines will almost certainly be considered for inclusion.

Since, it is impossible to second guess which they will be, the sensible, no-risk strategy is to improve accessibility across the board.

This article has been based on the Search Engine Optimisation and Accessibility guide. A free PDF version is also available.

Carmen Mardiros has worked in search engine optimisation since 2000 and has become an active promoter of web accessibility. She believes that improving access to web content is one of the most important elements in a web marketing campaign and also one of the key factors in achieving long term success. She is a member of the Bigmouthmedia search engine optimisation team, the UK's oldest established search engine marketing company, specialising in SEO, brand positioning, submission and placement.

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