I've been following Intrade for a couple of years or so. You are right, they call it right more often than not. It's an interesting trading model. I was going to put some $$$ into it for this election and related events, but didn't have time due to other commitments.
I would have made a big pile of dosh. Today, it says:
... pretty much how I figured how things were going to play out, at least as goes the presidency.