Not that I make anything more then pocket change for anybody, but I always try to sign up through an existing affiliate, and I do try to keep it in house. Whoever makes the recommendation (which I only trust from members of this board) usually gets my signup, otherwise I pick a board member I like who I know uses that sponsor and I go looking for a link on their network.
It's been years since I've added a sponsor without someone recommending them to me. I really should go do more sponsor hunting, not many of them are profitable now.
Greenie, I like your idea of requesting a referral in the "I'm looking for..." section. I'll be sure to do that from now on.