Also, if Intrade was so terrific, then why did they not reject the bogus exit polling and Bob Shrum on election day 2004 and keep Bush the favorite.
If Intrade traders are so fabulous at political predictions, why did they get duped by the Kerry campaign?
The problem with Intrade is the same as with any other self-selecting sample. Either they're trying to guess what happens next, or they're trying to force the results to some desired result.
What they're not -- almost by definition -- is a reliable predictor of anything close to the truth. At best, they're harbingers of what's already obvious. Mostly, though, they're just guessing.