There are numerous articles pointing out the business advantages of accessibility. Many of these reflect the similarity between accessibility and SEO. However, despite the close technical relationship between the needs of disabled users and the technical requirements of search engine optimization, the fact remains that the two goals are not the same, are not equivalent, and do not reflect the same ultimate goals.

At their hearts, web accessibility and SEO are focused on optimizing different aspects of your web site: accessibility cares almost exclusively about the disabled user and their experience whereas SEO is focused firmly on your bottom line and your experience, as site owner, in the online aspects of running your business.

Note: the practice of Search Engine Optimization unfortunately encompasses a wide variety of practices, many of which are not entirely choice. The practices referred to in this article are exclusively those “best practices” which are commonly described as “white hat.” Furthermore, SEO is an industry which focuses on both on-site and off-site factors; web development for accessibility is exclusively an on-site practice.

That isn’t to say that SEO (when done with best practices in mind) isn’t concerned with the user experience, but the bottom line for SEO is the marketing performance of the site. If it’s necessary to sacrifice some aspect of usability or accessibility for a measurable gain in the commercial performance of your site, the logical decision for search engine optimization is to make that sacrifice.

For the most part, SEO and web accessibility are very compatible services — the ways in which they differ are truly slight. From a technical aspect, all the same groundwork needs to be in place. However, when you begin to get into the finer details you can begin to see the subtle differences between optimizing for accessibility and optimizing for search engine success.

Site Maps

It’s subtle, but optimization is inherently concerned with subtlety. From an accessibility viewpoint, the best place for a link to your site map is at the top of the page, coupled with skip links. It should be visible and easy to locate, providing immediate access to your web site map.

From an SEO perspective, the site map — while very important — shouldn’t usually be given such key real estate on the page. For the vast majority of users, the site map is something they’re looking for as a purely secondary navigation method. Many disabled users, however, use it as a primary navigation method.

Alt Attributes

The whole debate concerning keyword in alt attributes has been thoroughly hashed over, so I’m not going to revisit the subject at length here. The fundamental difference is very transparent: SEO indicates that keywords in alt attributes (where relevant and meaningful) can be helpful to search engine rankings. Accessibility professionals are more likely to consider these descriptive alt attributes to be noise.

Although it may seem appropriate to describe every image in the site, it’s highly questionable whether this practice actually adds value, however well-composed and meaningful the attribute value actually is.

Headings and Titles

The broad outlines of what accessibility and SEO are looking for in headings and titles are very similar. They’re both looking for something which is immediately clear for the user and which explicitly describes the purpose of the page or section it begins. When it comes to detailed refinement, however, they’re likely to go in subtly different directions.

Accessibility practitioners want conciseness: the shortest unique label which can clearly convey the necessary information concerning meaning and context. This is simply an effort to minimize the noise factor for screen reader users and the learning disabled: reduce the time required to comprehend context and minimize the potential for confusion.

Search engine optimizers are less concerned with being concise and more interested with ensuring that the key terms and phrases are used in prominent contexts. Although it’s not necessarily true, it’s not uncommon for this to result in longer, more complex statements.


One of the best parts of the work I do is collaborating with search engine marketers. Hashing out these differences of opinion can be very productive. It’s a great way of hearing alternate perspectives and allowing both parties to gain a thorough understanding of the goals inherent to their processes. The differences between web accessibility and SEO (when done according to best practices, etc., etc.) are primarily a matter of intent. I don’t win every argument, and I can accept that: ultimately, the subtlety of these differences is such that I don’t really need to have things my way every time.

In the end, every site is a matter of compromises: meeting the line between what the owner wants and what each consultant or development firm involved in the project believes is best for the project.