I have heard some hype about promoting offers to members of Facebook groups, from new CPA marketers.
This is a really bad idea.
A colleague of mine went really big with this. He would pay off the owners of semi-large groups that could be messaged to and would message them his offers on a weekly basis. Although it was weakly targeted, he made a good deal of money with it. At his peak he was making 5 digits a month from it but Facebook eventually caught on, as did his CPA network, and he lost all of it to avoid legal action.
To any one considering this because it will make them a quick buck by sending crappy leads to your offers, DON'T.
White hat marketing does take more patience and time but it is a better route to take. A lot of the black hat approaches and temporary pay outs and will ruin your reputation as a marketer.
Do a lot of tracking, testing, learning, and promoting the proper way by trying new things and sending QUALITY traffic to your offers and you will become a respected affiliate within your network and will have first hand access to the best offers.