Warner proposed to Hotfile an affiliate deal where content that was taken down would be replaced with links to movie stores where users could buy Warner movies. More takedowns thus means more potential revenue.
Summing up, Hotfile accuses Warner on three counts. Violation of the DMCA, intentional interference with a contractual or business relationship and negligence.
http://torrentfreak.com/hotfile-sues-warner-bros-for-copyright-fraud-and-abuse-110913/