At the end of May 2009, the California State Parks Foundation (CSPF) was facing a budget crises and many parks were slated for closing or cuts to their services. In two weeks they were able to go from 517 to 33,000 Facebook Fans (Likes) and gain some press coverage in the process. This put pressure on the legislature to reduce the cuts to the parks.
Often times people want to help your cause, but they lack the time or money. Becoming a Fan (or liking your page) is an easy and convenient way for people to support you without spending much of either.
Read the full details of the campaign and the lessons learned on Marketing Experiments.