Under-appreciated YouTube change: Comments elevated to post status.
The most astonishing change in YouTube comments is barely discussed, which is that "Also share on Google+" is the default setting for comments. For people who leave this option checked, the video commented upon is posted on Google+ with the user's comment as the body of the message.
For example, this post you're reading now is just a comment on +iJustine
's YouTube video.
Doesn't that make YouTube videos a gazillion times more viral?