Apparently, there are two constants in the Social Media 'Verse. Number One, Facebook will regularly change our timelines and mess with us. Number Two, Google will regularly change how comments and comment notifications work and look.
And it's happening again.
Just a couple weeks ago, Google changed all YouTube video comments to an integrated Google+ system. That means that now, in order to comment on a YouTube video, you must have a Google+ account, and then when posting a comment, that comment may be posted to Google+ as a status update, along with the corresponding video.