Lol, It seems like most people on here play on at least one of those if not both...but somehow I doubt that everyone of them will reply to your thread! But anyway I am DPC3 on both sites but I mostly play FT. Also, some people have their different usernames listed in their profile, so sometimes you can use that if you are curious.
Most CardsChat members if not all play at poker stars and Full Tilt.
Usernames of members that want their names known can be found on members profile pages.