In the book Groundswell: Winning in a World Transformed by Social Technologies authors Charlene Li and Josh Bernoff share some their data on the "Social Technographics Profiles" (demographic use of social media) of Democrats, Republicans, and independents. What they found is that Democrats are "about 10 percent more likely" (pg. 55) to make use of social media than other groups. As noted in groundswell Barack Obama's campaign for President had tapped into this advantage with his social network for supporters: http://my.barackobama.com
The My.BarackObama.com site uses a couple of the Cialdini's "commitment and consistency" techniques to reinforce support for its campaign.
(Before I go on and imply that the campaign of Barack Obama is using trickery and deception to shore up support I want to disclose that I am a supporter of Obama and his campaign. Chapter 3 of Cialdini is all about consistency, right?). :)
When you set up a profile page at my.barackobama.com you are asked to answer a few questions about yourself. Some are looking for basic biographical information ("How do you want to be identified to others on this site?", "What is your birthdate?"). But based on Cialdini's writings the most important question on an Obama supporter's profile is "Why do you support Barack Obama?". By soliciting a reason from the new supporter the site is reinforcing the voter's support by also committing them to their reason for supporting Obama. Cialdini's data suggests this is a very effective strategy for sustaining support for the candidate.
It will be interesting to look at data after the election to see how effective the site was at getting its users to show up at the polls on election day. Do you think this method will increse support for Obama or will it just recommit the already committed?