All the prediction markets are closed feedback loops. Very little outside influance and what there is pales next to the insider trading. Wall Street is pretty much the same way, which is why it’s so regulated.

All polls are good for are trend lines. At this stage in an election cycle, what counts are demographics.
Polling is a subset of statistics and a dubious subset at that. Stats are based on randomness, which works well for molecules, but NOT for people.
There is very little random about humans. Your basic random poll isn’t random. It’s biased toward those that have land lines and the time and interest to talk over them. By the time you factor in those that lie and the slanted questions, there is very little in a poll doesn’t affect the standard error;

http://changingminds.org/explanations/research/statistics/statistics.htm

Polls are useless for results, but excellent for trends, since the errors tend to not affect trend lines.
Right now, Demographics are against BHO. He just doesn’t have enough groups (voting blocks) or the right combination of groups.
He is trying to do something about that, since him and his advisers are very aware of the basics of political science as practiced in a media driven voting population.
Right now the trend lines show Obama on a downward slope. My best guess would be that as he attempts to swap his voting blocks, he is facing resistance from both sides of the swap.
If he is successful in trading blocks, then he will win a narrow victory, If he isn’t, then we will see another Mondale type election.
Assuming, of course that Billery doesn’t strike at the Convention. That will depend on the trend lines. Going from 10+ ahead to a few points behind during July is not the sort of thing that makes a super delegate feel comfortable. BHO seems to have bought the votes of the Supers, or at least enough of them to get him over the top. Nothing illegal about that, since a Political Party is protected by the 1st amendment, but it does bring up the point that what was sold once can be sold again. Billery has a next door neighbor named Soros. Suppose she drops by to borrow a cup of sugar and a hundred mill or so? Then she has the funds to buy as many Super delegates as it takes. Isn’t that what markets are all about anyway?
The nomination is NOT a done deal yet, even if the Obamanics are pretending it is. Not ’til the balloons drop.