“YouTube Video Identification” is the name of the new technology, which is suppose to prevent illegal video distribution on YouTube.
The big studios and movie and TV companies will upload full length copies of their movies that will be stored on YouTube servers. When illegal copies are entered the YouTube Video Identification system will be able to recognize them.
Repeated offenders will be banned from YouTube, each copy will be coded, so exact copies of the same movie cannot be uploaded again and copyright holders will have access to one click “electronic notification and takedown tool", are some of the other anti-piracy measures that YouTube is taking.
Via: The Official Google Blog