Apparently, all the major premium video content producers require strong protections on the video stream. Currently Netflix uses Microsoft silverlight browser plugin.  They don't want people copying the raw contents of the compressed video stream (of course you can always screencapure the raw frames of an entire video, but in order to redistriubte the video contents on a torrent for example, it would have to be recompressed so it can download in any reasonable amount of time, which would of course produce many undesirable artifcats.)