Yea, GFY is an adult webmaster forum and they have a sales board there. Both of my 5-figure sales were to people on that board, plus the highest offer I've gotten on OTY.com has been there as well. The upfront aura one feels there is that most of the members there don't know what names are worth, but it seems to be the lurkers that don't really post but email and/or ICQ people and handle purchases and sales privately...they are the ones spending the dough. It's funny though because the high bids/sales I've made there have been of NON-adult names, and they've actually laughed at my pricing for some of the adult names I thought they'd be drooling over. I'm like "that's fine, I'm laughing too...all the way to the bank."
DP is just hilarious though. Looking through their names for sale, it's all about PR and backlinks...the name quality is kiddie extraordinaire...there's no rhyme or reason to the name quality there, it's all about what has PR and what doesn't. Pretty amazing really.
Meanwhile, the TRUE domain forums like NP and DNF are roughly the same for sales, though I've done more business here than there. I would imagine Domain State is probably similar too in name economy.