Jeremiah just posted a case study on the Facebook-Graffiti campaign. His summary:

Unlike most marketing campaigns that deploy heavy ads, fake viral videos, or message bombardment, this campaign let go to gain more. Overall, this is a successful campaign as they turned the action over to the community, let them take charge, decide on the winners, all under the context of the regeneration campaign. The campaign moved the active community from Facebook closer to the branded Microsite, closer to the corporate website, migrating users in an opt-in manner that lead to hundreds of comments was clever. Well done.