MyLot is my favorite because I can have deeper conversations with people and make new friends. I have written several tutorial hubs about myLot. I not only make new friends I've learned to care about there, but I also learn a lot from them. To top it off, I get paid for my participation, but income isn't residual. Every little bit helps, though.
I am also on Facebook, Google Plus, LinkedIn, and Zurker, but do not have many in depth conversations on those networks. Most posts I see are promotional in nature, whereas promotion is not allowed on myLot. Trolls aren't allowed there, either, and people have to be civil to each other on myLot.