Time has an interesting piece up today (I think it's web-only but can't tell for sure) about Obama's success at organizing Ohio. This passage kind of sums up the contrast with the Clinton campaign:
But it could be getting a bit late for that. All winter, the heart of Hillary Clinton's campaign in central Ohio was Jamie Dixey's apartment in the affluent Columbus suburb of New Albany. She started by inviting nine friends over to listen in on a national conference call with Clinton. She organized two monthly meetings, both of which attracted about 10 people. "It was very hard to get people interested because it was so early," Dixey says. In the world of traditional Democratic Party campaigns, this was enough to qualify Dixey as a star volunteer. She won an invitation to Governor Ted Strickland's rally on Jan. 19 formally kicking off Clinton's grassroots campaign in Ohio.
Dixey's counterpart on the Obama campaign, Valli Frausto, signed up to volunteer for Obama on Feb. 11, 2007, the day after he announced his candidacy. Immediately she found the social networking section of Obama's website, my.barackobama.com, which campaign insiders affectionately call "MyBO." Frausto posted a personal profile, just as she would on MySpace, and met other supporters online. Within six months, her group of three women had grown to over 200 members. Together they used the website's event planning tools to organize Obama for President picnics, neighborhood cleanups, phone banks and a 5K fundraiser run.
I think what we're seeing in state after state is that Obama is kind of the next generation of Howard Dean when it comes to building a grassroots organization. For those who are interested, I teased out that idea in this piece back in January.