Looks like a recent edit of the HTML5 draft about video support bent to the pressure of some corporation: Ogg Vorbis and Theora removed from the HTML5 spec.

See the diff. It is interesting to read the commit message:

Lift the cat who was amongst the pigeons up and put him back on his pedestal for now. (remove requirement on ogg for now)

I'll let you make your own opinion on the matter, but this is clearly not the right direction.