The Electoral College comes often comes into criticism but at least it is essentially just a weighted majority of pluralities. States, on the other hand, allocate their delegates in a variety of different and confusing ways. Right now news agencies seem to just count state wins but after February 5 expect some interesting analysis of delegate counts.
A little game theory: Why does John Edwards stays in the race when he has a virtually zero chance of getting a majority of the delegates? Because there is a non-zero probability that neither Obama or Clinton will have a majority either, and then Edwards wields incredible power with his small number of delegates. I don't know what Edwards would do with this power, but he won't give it up by dropping out of the race.
Notice that when we have a surprise victory in a primary, like Clinton in New Hampshire, much of the talk revolves on why the pundits, polls and prediction markets all "failed." Meanwhile in sports when we see a surprise victory, like the New York Giants over Dallas and then again in Green Bay, the focus is on what the Giants did right and the Cowboys and Packers did wrong. Sports fans understand probabilities much better than political junkies—upsets happen occasionally, just as they should.