When Christen Braun decided it was time to learn more about the presidential candidates, the 28-year-old high school teacher from suburban Pittsburgh turned to Google -- right where Sen. Barack Obama's campaign was waiting for her.
Her search triggered an ad for Obama's Web site, which prompted Braun, a Republican, to sign up for the Democratic senator's e-mail list -- and then to make her first political contribution, for $25.
Such transactions help illustrate how Obama has shattered fundraising records and challenged ideas about the way presidential bids are financed. While past campaigns have relied largely on support from small circles of wealthy and well-connected patrons, Obama has received contributions from more than 1 million donors. He raised $91 million in the first two months of 2008 alone, most of it in small amounts over the Internet.