TIP 17Does Google rank a page higher because of valid code? The short answer is no, even though I tested it on a small scale test with different results.

Google doesn’t care if your page is valid html and valid css. This is clear – check any top ten results in Google and you will probably see that most contain invalid HTML or CSS. I love creating accessible websites but they are a bit of a pain to manage when you have multiple authors or developers on a site.

If your site is so badly designed with a lot of invalid code even Google and browsers cannot read it, then you have a problem.

Where possible, if commissioning a new website, demand at least minimum accessibility compliance on a site (there are three levels of priority to meet), and aim for valid html and css. Actually this is the law in some countries although you would not know it, and be prepared to put a bit of work in to keep your rating.

Valid HTML and CSS are a pillar of best practice website optimisation, not strictly search engine optimisation (SEO). It is one form of optimisation Google will not penalise you for.

Where can you test the accessibility of your website – Cynthia Says – http://www.contentquality.com/ – not for the faint hearted! :)

Addition – I will be following W3C recommendations that actually help seo;

Hypertext links. Use text that makes sense when read out of context. Top Ten Accessibility Tips

Did you know when you link to a Hobo SEO post we have search engine friendly links back to your site if approved? Our comments are also search engine friendly you know (once you've commented on a few posts)! Do you need any more encouragement to get involved in the conversation ;)