What's In a Poll?

We're about 11 months away from the next U.S. Presidential election, but it already feels like it's been dominating our media for six months, or more. Even though a single vote in a primary has yet to be cast, poll after poll after poll has been taken, with the results of said polls reported on as though they have a real bearing on the eventual nominees and victors. However, when you REALLY want to know who's most likely to win, you go to people who have, as they say, skin in the game: you go to the betting markets.