Valid HTML for Better SEO?

One million question:  should I fix HTML errors for better Search Engines ranking?

Guess what: NO

-And why is that, dude?

Because even if your code is 100%  valid, it does not mean that your page is the most relevant on the planet for some search query.
By the way, i don’t think that uncle Goog will spend his valuable crawling and indexing resources in order to check HTML errors.

-But why so many people talking and arguing about the issue? What’s the deal with SEO and HTML validation?

It’s simple: let’s say, that you have unclosed angle brackets at your page:  <p   The best website in the world!</p>

In this case, the crawler will pass over the whole text – because for every  (“<”) should be  (“>”). Anything between those two angle brackets must be HTML, Java Script or inline styles, so in this case the content will never rank for “the best website in the world” query.

Another example is unclosed tags: Most of the tags should come in pairs. If  you accidentally forgot to close any link tag, that started as “<a>” and never ended with “</a>” , the rest of the content after “<a>” will became a link.

Other funny case, is when image “alt” tag looks like: <img src=”images/boo.jpg” alt=“boo />
so my guess is that the alternative text will be boo+rest of your code. This is too obvious -  it’s really bad for SEO

In summary, it is always good to check HTML errors for any unclosed tags or “broken” angle brackets for better SEO, but there is no reason to validate every HTML error, that you may find. Unclosed <center> will center the rest of the page, but the content will be visible for users and Search Engines.