It's about Google rankings algorithm.
Correct me if I'm wrong but I never read it anywhere else. The idea is the following.
Let's perform a search with the keyword animated website, look at SERPs (the first page review will be enough) and then do the same search "animated website" (with quotes) withing SERPs first page sites (go to each site and do on site search). It's easier to do it via Googlebar. site:sitename.com "animated website" and pay your attention where you find these two words keyword (page title, anchor text, plain text).
The sites on first SERPs have many pages contain this keyword (exact match within title is the best way to be ranked higher). I'm not saying this is the major ranking influence factor, but definetely the important one.
Google anylize the whole website for any given keyword to calculate this keyword weight on a website.
ps. www.looneytunes.com has his first place because of huge inbound links number ;-)