Today I’ll be as brief as possible, as deadlines are getting closer and closer ;/ Sorry in advance.

Anyway, I’m gonna write a bit about my latest toy - Facebook integration. I were never a fan of Facebook, but after getting acquainted to the APIs, I must say that I’m impressed - it’s well thought through and extensive - you can act as (on the level of) a user but also as "an application" (for instance, a web-page that can be ‘liked’ / ‘recommended’ / etc. Your integration may be performed both on the level of UI ("web-pagelets") and service (both client and server layer) and the variety of technologies that can be used is very wide.
If you’re much into .NET (Facebook loves other technologies more…), you can try this API (I’ve used it and it works quite fine): http://csharpsdk.org/
Happy facebooking ;P