Source: http://www.engadget.com/2013/11/06/youtube-comments-google-plus/
Back in September, YouTube revealed its plan to overhaul comments on the video site with the helping hand of Google+. Now, that new system has gone live. Conversation-style commenting that ranks based on a number of key factors (like people you know), allows private notations solely for those in your Circles and serves up easy moderation in order to quell the naysayers like word filters and auto-approval. The new Google+-powered system should be popping up on YouTube channels that you frequent soon as the global roll out has already begun.
Via: TechCrunch
Source: YouTube