The subject matter of this specification can be implemented in, among other things, a method that includes receiving, by a processing device, one or more first content items for one or more first user accounts of a content sharing system. The method further includes storing the first content items at the content sharing system. The method further includes receiving, by the processing device, a second content item for a second user account of the content sharing system. The method further includes comparing, by the processing device, the received second content item to the stored first content items to determine that the second content item is not exclusive to the second user account. The method further includes restricting a privilege of the second user account for the second content item in response to the determination that the second content item is not exclusive to the second user account.