Learning from Obama: Lessons for Online Communicators in 2009 and Beyond is based on a series of articles written by Colin Delaney of epolitcs.com shortly after the 2008 campaign.

It's an excellent overview of how and why Obama won and how you can harness many of the same strategies to replicate what was done for his campaign. NationBuilder allows you to implement practically all of the methods discussed here, so it's definitely worth a read.