Ogg as a fallback for Linux... Actually Theora was seriously planned to be the codec for HTML5 video, but Apple and Nokia spoiled this in 2007 due to some virtual patent problems.
That's known, but Theora never could compete with H.264 in quality. It was proposed simply because it was the best available open coded at that time. When VP8 arrived it replaced Theora for that role.
It's not that bad, moreover the game is always about quality/quantity ratio. And if it had become a standard, its development would be heavily pushed forward and vp8 would likely now be really free and called theora 2.0.
