Read this little bit about the fan promotion of the movie Serenity (best movie ever) and how the studio reacted:
As the release date neared, fans tried everything to raise the film’s profile, from holding bake sales to selling amateur-designed T-shirts. Once the box office returns were collected, Universal Studios (who produced the movie) sent out a series of cease and desist letters to the fans and, in some cases, sought to collect retroactive licensing fees for the production of T-shirts featuring Serenity icons. The fan community responded by tallying up the time they had spent in promoting the show and then sent Universal an invoice for more than $2 million (28,030 man-hours). Universal quickly backed down.
Hilarious. Power to the people!