“People who look to Intrade for insight are idiotic.”
Evidence? Even skeptics of political markets concede that the predictive power of sites such as Intrade GENERALLY is superior to reliance on political polls:
“Indeed, three days out of four, a poll will be less accurate than the vote-share market price at predicting the election outcome. Someone who played the vote-share market based on the expectation that the division in the latest polls would translate one-to-one into the final vote division would lose decisively in the long run.”
http://www.edwardtufte.com/files/MarketsandPolls.pdf
It's not predictive. It's reflective. Intrade simply reflects conventional wisdom as published by sites such as Cook Political Report or RCP. It's thus a lagging indicator of external data. Except that it's easily subject to market manipulation.
In summary, it's crap.