I've gotten a chilly reception from poll enthusiast Steve Vaillancourt both times I've mentioned Intrade in comments on his blog. He'll probably like me less after I post this blog by John Sides at The Monkey Cage.

The Constant Attention to Individual Polls Is Hurting America

A short excerpt:
Poll results vary for random reasons—that is, because of sampling error. ... we don’t actually know the true proportions of Obama and Romney supporters in the public.  There is no way to know definitively which poll is “the truth.” ... not only don’t we know Obama’s or Romney’s true share of the vote at this moment, but we don’t know with much confidence how much any pollster might be systematically overestimating or underestimating Obama’s or Romney’s share of the vote.  For that reason, if you just want to know where the horserace stands, look at the average of the polls and ignore the individual polls.