His nickname as a pool player was "World Class" because he was that good, he shortened it to just "world" when he switched to poker, at least that's the story I heard. As for his skill at poker, it's unquestioned, the guy wins more in cash games than most players win in tourneys; only now that the prize pools are worth his time is he begining to play. My girlfriend was working at the Bellagio and saw him win over a million dollars in pots, in one night! The guy is world class.