The hazard of early voting is that you can end up simply time-shifting your likely voters. That is to say, you don't make the voter pie higher, you just parcel it out over the course of a couple weeks. The Obama team has smartly focused their early voting efforts on turning out otherwise unlikely voters.
....after the first week in early voting, the [Democratic] party also enjoys a commanding lead, based on the party affiliation of who is showing up at polls.
"Much of our energy in the early voting is to persuade those erratic voters to get out and vote in early polling locations," [Deputy campaign manager Steve] Hildebrand said, citing Floridians who don't tend to vote every election cycle. Their eyes are especially on the hundreds of thousands of African-Americans and young voters who didn't vote in 2004.
Hildebrand wouldn't reveal how many of the voters showing up so far were among their targets, but did allow that the rate was where they wanted to be.
"Right now, we're in a good place," he said. "We're a few points ahead and have been consistently for about 30 days. Organizationally, he's going to have a difficult time matching us on the ground."
Hildebrand's a straight shooter, and given the campaign's current determination not to count chickens, I'd say he's looking at some great numbers to be talking this optimistically.