First of all, none of my friends have any red cups or are dressed in slutty costumes, so if you're mirroring your FB experience to someone else's then words to the wise - it may vary.
At the moment, for myself, it's the ultimate best way to:
-Stay in touch with friends near and afar
-Organize events and happenings
-Get info on gigs and parties
-Hold long group convos that everyone checks often
-Post pictures of cats
I'm a bit introverted at times and Facebook has really connected me to a booming social life more than anything before, contrary to what some posters have mentioned about FB somehow interfering with actual real-life contact with people.
As for statuses, pictures, links etc... I share what I like, and although I try to regret nothing in life, I don't post anything too illicit or criminal on there. It's just bits and pieces.