People sometimes ask whether Google should boost (or penalize) for valid (or invalid) HTML. There are plenty of clean, perfectly validating sites, but also lots of good information on sloppy, hand-coded pages that don’t validate. Google’s home page doesn’t validate and that’s mostly by design to save precious bytes. Will the world end because Google doesn’t put quotes around color attributes? No, and it makes the page load faster.
Eric Brewer wrote a page while at Inktomi that claimed 40% of HTML pages had syntax errors. We can’t throw out 40% of the web on the principle that sites should validate; we have to take the web as it is and try to make it useful to searchers, so Google’s index parsing is pretty forgiving.
W3C Valid Code & Google
