I noticed the Google+ integration YouTube has been testing out on the Kony 2012 video I watched last night. Notice in the bottom right hand corner, just below the view stats, it shows that a few people have shared the video through Google+. The second screenshot shows that YouTube has added Google+ as a share option along with Facebook and Twitter.

Screenshot of YouTube Videos & Google+ Integration

YouTube Social Sharing Options, Including Google+:

Screenshot of YouTube Social Sharing Options