In Indiana, ahead of Tuesday’s primary, Obama supporters can go to a campaign web page devoted to the state, type in their ZIP codes and locate the closest pro-Obama group, such as Bloomington for Obama, or Central Indiana for Obama…. The networks ultimately created legions of contributors…. One highly successful strategy, he said, entails inviting supporters to match contributions from first-time donors – a process that ends with the two donors emailing each other about how and why they got involved in the campaign.