Check this, pretty interesting...
"Perfect 10 Inc., which publishes an adult magazine and operates an adult Web site, says hundreds of Web site operators around the world are selling its trademarked images. While Perfect 10 has sued many of these outfits, its biggest beef is with the credit card companies that process the infringers' transactions. The porn company says that without the support of these financial institutions, infringers wouldn't be able to steal their stuff."
http://www.nylawyer.com/news/04/06/060704e.html