Why would an FAQ page rank above a site’s homepage?

Matt's answer:
CUTTS: We have a question from Alex in Germany. Alex says, “Sometimes, when you search for a company, you won’t get the main page as a search result. For example, you search for [example company name] and you get their FAQ page listed first. How does that happen and how can we avoid it on our own websites? Well, typically, it happens because that FAQ page or F-A-Q or where the particular page that shows up is the page that’s getting the most links. So, for example, if you search for my name, Matt Cutts, we return mattcutts.com/blog instead of mattcutts.com at number one. And the reason for that is pretty simple: because more people link to my blog than my root page. My root page doesn’t really have that much information on it. It pretty much just has one link that says, “You probably meant to go to my blog.” So I think my page rank is seven or something like that on my blog and only five on my root page, so what that means is the vast majority of reputable links are pointing to my blog. So, in those kinds of cases, we think that deeper page is better than the root page. Now, the vast majority of the time, the root page is what attracts the links, so it’s–what has the highest page rank? It’s the page that we think ought to be returned first. But it can happen if you have one page that goes really viral or something like that. I would make sure that whatever page you want to rank number one, you know, if you have another page ranking above it, add a link to that page so that the page rank will flow to that page that you want to have ranked. But most of the time just the root page should rank naturally, and you don’t really need to worry about, you know, that sort of thing. Making sure all your linking is consistent internally so you’re always linking to the root page with either dub-dub-dub or non-dud-dub-dub, whichever one you want it to be, well, make sure that you don’t accidentally split your page rank between those two pages. So there’s some things that can happen where, you know, we think that these are two different pages, but as long as you’re linking relatively consistently and you’ve got links coming from the outside world in a normal sort of way, most of the time, just your root page will show.
by Matt Cutts - Google's Head of Search Quality Team