Is hiding text with CSS to improve accessibility bad for SEO?

Almost five years ago I posted an article titled Google, SEO and using CSS to hide text. In the article I brought up the possibility of getting in trouble with Google and other search engines for using CSS to hide text for accessibility reasons.

Both at the time and several years later the general reasoning among developers (at least as far as I am aware) has been that as long as your intent is not to fool the search engines you should be fine. But is that still the case?

The reason I’m asking is that a client has hired an SEO company that claims using CSS to hide text – any text, for whatever reason – is likely to result in an automatic search engine penalty. Not necessarily a complete removal from the index, but a lowered ranking.

Techniques that this affects are various image replacement methods, positioning content off-screen (sometimes also called the off-left technique) and other methods that involve using CSS to hide pieces of text from sighted visitors but not from screen reader users.

Considering that many people have been using these techniques for years and seem to be doing just fine with search engines, I really wonder if there is any truth to the SEO company’s claim.

What does Google say about hiding text then? The closest thing to an answer I’ve been able to find is the following from an article called Hidden text and links on their Webmaster Central (emphasis added by me):

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?

The intent of hiding content to improve accessibility is most certainly not deceptive. Content hidden for that reason is there for visitors who can’t see the screen (or who happen to be using a text browser that doesn't support CSS). Sometimes that includes search engines.

Obviously hiding heading elements stuffed full of keywords should be penalised. But one would hope that a manual review is performed to avoid incorrectly penalising sites for hidden content that is not “deceptive in intent”.

Does anyone reading this happen to have any reliable and current info to share? Does it matter which CSS technique is used to hide content? Does it matter what HTML elements are hidden? Pointers to a definitive and authoritative answer would be fantastic.

Posted on October 11, 2010 in Accessibility, Search Engine Optimisation