YouTube, which is owned by Google, made substantial changes to their commenting feature this week. and if you've tried to comment on a YouTube video, you may have noticed some changes.

Chief among those changes is that commenting on YouTube now requires a Google+ account.  Google+ is a fledgling social network looking to gain market share against Facebook and Twitter.

This text appears as a pop-up in the Comments section of YouTube:

Smarter sorting

See more from people you know.

Meaningful conversations

New threaded format and +mentions encourage discussion.

In more places

Comments appear from both YouTube and Google+.