A recent tweet from Google’s Gary Illyes called attention to problem of invalid HTML. Google is fine with invalid HTML. Less well known is that there are negative outcomes associated with invalid HTML ...

Most top-ranking websites fail HTML validation. Google explains why perfect code isn’t required, and what matters instead. Many top websites have invalid homepage HTML, yet still rank well.

When Google updated their Webmaster Guidelines yesterday, one of the changed was changes was around valid HTML. Before it read, "Check for broken links and correct HTML." and now it reads "Ensure that ...