At least the last time I checked, which was a while ago, it is not used as a direct signal within our ranking. So it’s not one of the over 200 different signals that we use to assess the quality of a page. But I think it would be fair to think about using it as a signal.
So for example, we noticed a while ago that if you look at the page rank of a page, so how reputable we think a particular page or site is, the ability to spell correlates relatively well with that. The sites that are lower page rank or very low page rank tend not to spell as well. Which is a pretty interesting effect, if you think about it.
We’ve also done a little bit of studying, and there’s actually a guy, or team of people, who have produced reading levels. So is this written at a 3rd grade level or is this written at a 12th grade level? And so that’s the sort of content analysis that would be pretty interesting to explore as a potential quality signal.
I can tell you there will always be issues with any signal that you try to compute. So for example, take spelling and grammar. There’s an inherent assumption in that question that you are talking about the spelling and grammar of a particular language. And so in order to figure out how the spelling is and how is the grammar, you have to figure out what is the language of that page. And even if you have the best language identification in the world, over tens of billions of documents, you’re going to find that maybe there’s a few pages that you missed. And so you might think that this page has awful spelling or awful grammar, but it turns out it’s really just in Hungarian instead of in English. Or maybe a paragraph or two is in Hungarian, instead of English. And so it’s not the case that you can automatically say, aha, this will be a perfect signal. That’s why we try to do a lot of evaluation.
We do a lot of testing to see whether something is really a quality win, whether it matches our intuitions. But it is the sort of thing where it turns out in our experience the more reputable pages do tend to have better spelling and better grammar.
Probably users will appreciate it. People can understand when they land on a page whether something is a little bit knocked out quickly versus somebody put a lot of work into it. There was a copy editor or someone did some fact checking or they’re an expert on the subject. And so, when at all possible, I certainly try to pay attention to spelling and grammar, even when I tweet. Sometimes you mess up, but it is something that I would encourage people to pay attention to, maybe not necessarily for the search rankings directly, but just because it’s a good experience for users and users appreciate that. They’ll be a little more likely to bookmark you or come back or tell their friends about you. Hope that helps.
by Matt Cutts - Google's Head of Search Quality Team