([img ]http://i.imgur.com/u7Yo0Vy.gifv[/img])
Yep, just what I expected. Good luck embedding this kind of stuff in any forum, for the moment. Web standard acceptance might also take a while.
This isn't overly clear to me from the info, so I hope the adaption will come at the file format level (that is, .gifv will be treated like .gif images are treated now) with the encoding (and decoding) happening via .h264.