As of December 1, 2016, the U.S. Copyright Office will be decreasing the fees to register a “notice and takedown” agent to $6.  Any website (including social media site) that accepts third party content may be interested in taking advantage of the “safe harbor” offered in the U.S., and those that have already registered an agent will need to update the registration.  You can find more details on our sister blog, the Brand Protection Blog, with this article:  http://www.thebrandprotectionblog.com/copyright-office-to-decrease-dmca-agent-registration-fees-by-94/