It always lowers my opinion of a comic if just about all his jokes are jokes someone else couldn't tell. I don't mean he has a unique delivery that add to the jokes, but they are ethnic and or size jokes. I think it pretty much summed it up when this fat black man took the stage and said, "It's fat nigger joke time". Don't get me wrong I don't hate these jokes; I just don't think they have the power or imagination of 'global' jokes.
I think one thing that makes people laugh in a comedy club is a bit of discomfort. A stage comic needs stage presence. A good comic has an air of charisma (with the exception of comics that use anti-charisma as their shtick - e.g. Emo Phillips). Charisma makes what they say funnier by giving their statements an air of truth.*
Comics can quickly establish this charisma by raising themselves about you by making you feel uncomfortable.
Back to my point, a charismatic comic wouldn't need to do that. A better comic is able to do that with global discomfort, jokes of anal sex and overly large vibrators usually do the trick.
Anyways,
* - Anti charismatic comics automatically have the air of truth because they are dissing themselves. Try to imagine Emo Phillips making fun of women using large vibrators for anal sex, it would just be strange.