Mashcode's got a list of facebook apps right here...and it's a classic case of taking the API and making it available to a great set of services--Feedburner, College Humor, ilike, dogster--there's plenty for everyone.

Isn't there an obvious question here why other networks with larger user bases haven't developed their internal APIs in a way that would fuel this kind of development?

And another question about whether facebook's investment will accelerate that movement?