Can coding errors affect how a page is indexed

We have a fun question from Ryan in Dearborn, Michigan, who asks: previously, you mentioned that W3C validation isn't a ranking factor.

Some people took this to mean that coding errors can't effect SEO.

Many don't believe that.

Can you give some examples of HTML errors that can effect SEO?

Well, there's this spectrum where on one side of sight, W3C validates, it's really clean, it's really easy to update.

If you can do it that way, I encourage it, but you don't get a ranking boost. On the other end of the spectrum, there's people who make really, really sloppy errors.

They're coding a site by hand, they might not close their tables, they might have lots of nested tables.

So what we try to do is we have to crawl the web as we find it, and try to process it well.

So we handle sites that don't necessarily validate, that have some simple syntax errors.

But it is possible to have degenerate web pages that can effectively cause your page not to be indexed.

So if a page is hundreds ofmegabytes long, that might notget completely indexed.

We have seen, in some verylimited situations, where we'd have a regular expression where we tried to match something.

And it would match the first half, and then people would go off and have almost random gibberish text.

And so the regular expression eventually died and broughtthat computer down with it.

So in processing the web, we found there were a few documents that would tickle the problems within this particular regular expression.

But for the most part, if you have a reasonable page,something that most users can see, we will be able to process it.

We will be able to index it.

So the easy way to check that is open it up in a text browser, or two or three of your favorite browsers, make sure that you can see the text.

If all that text is visible, then it should, for the most part, be able to be indexed by Google.