What do you think of InTrade and other such "prediction markets" short/long term?

[Leaper]

Sites like InTrade allow people to use real money to purchase "shares" of futures in predicting political, economic, and other (non-sports) events, sort of like a stock market for political punditry. (Except, again, you use real money.)

What do you think of such sites as a predictor of future events? There are two different ways to think of their predictions:

* Long term: as an indicator of best conventional wisdom of what will happen. Is such a concept worthwhile?

* Short term: via trends and individual buys and sells - for example, around 8:30 tonight, someone a LOT of money against Barack Obama winning the Presidency; that has led some people to think that this person has inside info about an upcoming event or announcement - such as one McCain's said he's going to make this morning. Is such a move an accurate indicator of immediate future events, since there's real money involved?