Which is to say, very little; and that's perfect for Democrats.
(The) Joe Wilson moment(was)a serious breach of decorum (in the U.S.) that served to underscore the exact point Obama had been making: we’d like to have a substantive contribution from Republicans, not the lying – his word – histrionic nihilism we’ve been seeing. Cue Joe Wilson with lying histrionics. Well done, Joe. It pissed people off, made a money-bomb for his opponent Ron Miller, and was similar to the way Dems (although certainly not Republicans) reacted to Sarah Palin’s acid floor speech at the convention on Sept 2, 2008. We saw the few Republicans who were in field offices last year motivated by Palin’s presence on the ticket but not McCain’s; we also saw many more people showing up to Obama offices in part galvanized by opposition to her sneering speech (and overall Palinosity).Sean Quinn, Five-Thirty-Eight.com
I couldn't have said it better myself, and I wish I had coined "Palinosity".