Micah Sifry says a comparison of the Obama and McCain ground-game apps shows "a lopsided battle in their voter contact operations...Obama's tool is much more deeply embedded in the ecology of the internet than McCain's, by a factor of anywhere of a hundred to a thousand times."

Folks more knowledgeable than I about political campaigns argue about the importance of get-out-the-vote efforts and other aspects of the ground game.

A famous campaign strategist told me recently that messaging matters more than the field effort, and that the strength of Obama's big organizing push is in having thousands of people spreading the word. Other people swear that the ground game can have a more direct effect in producing a critical margin at the polls.

So far, events in my home state of North Carolina seem to validate the ground gamers. The huge turnout for early voting favors the Democrats, and the specific goals of the Obama ground game include early-voting turnout. I don't think that's just a coincidence.