Google Chrome is shipping Theora/Vorbis. They ship it as well as H.264 in Chrome, but without H.264 in Chromium (as they can't licence the patents).
Opera has had Theora/Vorbis supporting builds for a while. It seems very likely they will go with Theora when they launch full support.
Note also that Xiph Qicktime codecs allow Safari to use Theora as well. These codecs should just intsall from the net when you encounter such a file, but while we wait for Apple to get around to that they could easily be piggy backed onto one of the many pieces you need to install to get all video working well on Mac OS X (Perian, VLC, mplayer, or even Mozilla Firefox)
It may only be mediocre or "good enough", but it is "free". If you don't understand the importance of that to the web then congratulations on your lack of "ideology".
Or maybe letting some random corporations place a tax a vital part of our technical infrastructure in return for marginal technical benefits is an ideology, just not a very good one?
Until a few months ago when they made a breakthrough in the development version of their encoder, Theora was the WORST mpeg4-like codec in active development, much worse than h263 (which is itself awful). Double the bitrate / encode times and half the quality -- it hadn't really improved at all since it was open sourced.
Now it's no longer the very worst modern codec (beating h263, but still mediocre), but it's at least 4 years too late.
Vorbis audio is widely used in commercial game development because it's very free and very good at low bitrates. Theora has only been used by agenda-driven freetards, basically just Wikipedia. Mozilla will likely be the only browser vendor shipping Theora and not h264. Apple and MS will never ship Theora, and Google is currently only shipping h264.
I wouldn't have a problem with people advocating its sole use for ideological reasons if it wasn't dogshit for so long (and mediocre now).