I haven't seen the film yet, but I watched a bunch of clips on youtube and laughed my ass off. I didn't like the Ali G character and I don't think he was big hit here in the U.S. It's probably because I had no former knowledge of the comedian and when I saw Ali G., I thought: "Yeah, an obnoxious rapper. Just what I need another of." I guess I didn't give him enough of a chance, though, since Cohen is obviously a very funny guy.
I think the reason why Borat is so much more instantly popular, and will be a HUGE, success is that America needs Borat at the moment.
If you dissect his character, he's exactly what we need to find some relief from the war. The world can point its finger at the brutish Americans and the war in Iraq, but we're just as stressed out about it as the rest of the world (of course, with the exception of poor Iraqis themselves).
If you look at Borat's character, he fits "middle eastern" very well. Like the images of Arabs or Muslims of Iraq/Iran/Afganistan we glimpse on TV. He may be meant to be an eastern european character, but he's "foreign" enough for the average american to lump him in with all these little known countries we've been forced to face and fear since the war on terror began. Kazakhstan -- just the sort of place we've had to wake up and go: "Huh, where? They're out to kill us?"
What I'm saying is that Borat is providing a huge dose of stress relief for Americans who have been forced to fear persons from abroad. He's a great, silly charicature of the "backwards" people we're now fighting. And since they apparently loath us, Borat's our chance to laugh back at them and have them undemonized. Think back to the World War II movies and cartoons where the Japanese were parodied -- for a moment we could lose our fear of the Japanese under their lampooning, charicatured in the broadest possible way. The same with Borat - he's just what we need to cut down the scary, threatening dark-haired person to size. It's a laugh of relief I think America is feeling toward Borat.
Now, I'm not saying this to in anyway undercut Cohen as a comedian. He's a master. His timing is impeccable and he understands classic comedic conventions. And, of course, in the way that the Marx brothers were pretty awful characters (and Chaplin's tramp) he's genius enough to make us love Borat.
Who knows, maybe it's Borat who will bring peace to the world>