Michael Moore is the closest I could come up with. What makes Coulter unique is that she actively tries to offend liberals. I can't really think of anyone famous for trying to offend conservatives (although lots of people have become "almost famous" that way.)
They're not alike in their tones or most famous aspects -- but their appeal to their ardent fans is similar. "Here's truth that the [corporate|liberal] media contrives to obscure." Each offers a mostly self-consistent (but in other ways bizarro) world to make their audiences feel among the enlightened minority.
I happen to think both sometimes make useful and thought-provoking points, though followup conversations about them are prone to derailment into all sorts of superficial reactions and over-rehearsed ideological set-pieces.
I agree with "both sometimes make useful and thought-provoking points".
The problem is that these people create true believers. The world could really use sane alternate viewpoints -- and we mainly get lots of conspiracy theorists unable to change viewpoints.
I am European, so the only thing I know about Coulter is that she is some form of right wing crazy; a less formally polite Chomsky... :-)
That is also more than I care to know; the US extreme left/right looks equally insane. I just wish neither was popular here. But I guess you get the good with the bad.
I agreed with a quote as a way of saying that they generate hypotheses that probably aren't correct, but potentially fruitful to work from.
Seriously, tho', Chomsky? Would an Ann Coulter diatribe last as long?