By many definitions of "open standard" H.264 isn't one, since many groups tried to brand that term in echo of "open source" to mean royalty-free (and therefore open source compatible). That definition seemed to generally be catching on until this web codec spat flared up with both sides wanting the cachet of being "open standards" rather than debating the actual policy implications of being royalty-bearing.
And factually there's several independent WebM implementations now, some would argue that it's easier to be compatible with an open source codebase than a spec, though having (at least) two independant codebases developed before finalizing is better for finding spec bugs.
