Carbon Poker is part of the Merge Gaming Network. It is licensed by the Kahnawake Gaming Commission and is one of the few online poker sites I know of that hasn’t had a major scandal or FBI investigation launched against it (not yet anyway, as of 4/22/10.) Carbon Poker also offers 35 % rakeback which is one of the highest percentages out there and they allow US players. As with most online sites rabbit cams are available, bad beat jackpots, and much more. Players also have the option to show only one card (as opposed to having to show both.) Deal it twice (as seen on High Stakes Poker) is also available at certain tables.
Players on Carbon Poker will also have the option to play against players at PDC Poker.