Facebook today launched a feature called Lexicon, which mines wall posts for word patterns:
Lexicon is a tool to follow language trends across Facebook. Specifically, Lexicon looks at the usage of words and phrases on profile, group and event Walls. For example, you can enter "love, hate" (without quotations) to compare the usage of these two words on Facebook Walls. You may enter up to five terms, where each term can be a word or two-word phrase consisting of letters and numbers.
I’m sure this will be interested for linguistics majors out there.
The bigger feature released today is the on-site chat. It doesn’t require any downloads so it already beats MySpace chat. Congrats, Facebook.