If you send a friend request to a forum buddy (be it from yahoo, mc.net, CCC, SAAC, gardenweb, etc.), you might want to shoot them a note on FB & reference your “handle” on the forum. Personally, I don’t accept friend requests unless I recognize the person’s name, I imagine a lot of folks have the same policy.
I don’t spend a bunch of time on FB, but I do check it out a few times/week on my train ride to/from work. 