I'm suprised they are not worth more since they represent a great point of entry for social attacks. Think Personalized spam (i.e. "Hey John, I think Laura wanted you to buy this for the concert you are attending next week"), targeted dictionaries, localized phising (i.e. location data deploys phising to compromised machines near you). Once you break a single friend in the "network" you gain additional information to everyone in that scope, so the return on entry is very promosing. An attacker can begin profiling ideal targets in the guise of friends. Ah, so many possibilties. Such a gold mine.