I knew about this from some time... that we had introduced a full screen support with the new Flash Player (get it). But i never realized until i saw this on Abdul's blog that it was being used so tastefully to improve the user experience on the web.
BrightCove.com has come out with a new video player with full screen support. Check it out.. its awesome.
What it has also done is that peole have started rolling out video channels online... like the TasteTV.com (which uses brightcove's player) and Sony's MusicBox. See this John Mayer Channel by musicbox. The online video revolution is just starting.
Here's another blogpost by Manish on the same.
And do checkout this awesome Panorama Viewer