ACORN is a favorite subject for rageoholic Twitterers and few others, and I suspect it won't sway many undecideds. But John G. Geer figures it's all a good thing anyway: In a Post op-ed over the weekend he argued that negative ads, if nothing else, get down to specifics. Geer's written a book-length study of the subject, but those with short attention spans can go straight to his "Attack Ad Hall of Fame." It's probably only a matter of days before McCain posts an ad featuring 25 seconds of Barack Obama's face and five seconds of a mushroom cloud; at least you don't need Fox News' permission for that.