Let's see.
AVN / Adbrite
Party Poker
Ebay (they buy traffic through "auction ads".
http://www.btmon.com/Porn/Movies/Por...N.torrent.html
Fling
Porn sites owned by whoever owns straponstudio.com (whois privacy and no program info on their sites, but hosted at (gasp) National net
Etology (click seller)
http://www.demonoid.com/
Zango, and as a result anyone who buys traffic from zango.