Most of these are fairly low volume. Granted there were some more high volume ones that were sure things, such as shorting Paul to be the GOP nominee or Gore to be the Democratic nominee. However keep in mind at his peak Paul was still running at about 7. Bid $100...win $107 (before InTrade fees.) Even bidding $1000 would only win you about $1070, an extra $70. So is it worth it to have that $1000 frozen for that long? If you had enough money to where it didn't matter, the $70 wouldn't matter either. That's the main reason I never invested.
well, the thread was based on the idea that it's easy money, unlike stocks where you can lose your shirt. Let's say you have $10,000 to invest today, and don't plan on using it for at least 6 months +. You can buy stocks if you like, and hope to get a decent return... or you can get 7% via intrade investing in the election (arguably a sure thing), which means in November you'll have $10,700 to invest... that's a pretty hefty return in 3 months...
On the other hand, depending on the state involved, there is always a 5% or so chance of some sort of major shift in the electorate - a major gaffe, a big international event, something that changes the dynamic of the race. As the race is today, of course McCain CAN'T win in Washington, and Obama CAN'T win in Arkansas, but some unforseeable event could lead to a true landslide allowing some of those states to swing wildly enough to change the winner. This is even more true with states like Montana, Indiana, Wisconsin, even New Jersey, under the right scenario. Elections are a snapshot in time and we are still 3 months from election day.
