People you want to bang aren't always Facebook Friends
signup.bangwithprofessionals.com
signup.bangwithprofessionals.com
I think that we've seen this business model already. You get an email saying that someone you know wants to bang you. Curious, you register, and won't get told the person - you have to go through everyone you want to bang, and guess each one. If you guess, the two of you get matched. In the meantime everyone you guessed at gets an email from you.
The result is a lot of annoying spam, and before long the service becomes undeliverable to anyone and dies out. (But every stalker who hears about it will love it!)