I believe that most of the DMCA compliance can be done automatically through the use of Content ID.[1] Basically, for partners that they have a Content ID relationship with (e.g. the big entertainment companies), they can automatically determine infringement and whether they should take the content down, or if it's OK to leave it up.
Obviously there are plenty of people who aren't using the Content ID system and are sending in traditional DMCA requests, but I imagine that the automated system takes care of a big chunk of the work.
Obviously there are plenty of people who aren't using the Content ID system and are sending in traditional DMCA requests, but I imagine that the automated system takes care of a big chunk of the work.
[1] http://www.youtube.com/t/contentid