I posted this as a comment on another thread; but I thought it warranted its own post.
Webkit is an open source project.
Webkit development is sponsored by corporations (Apple and Google primarily).
Webkit includes support for h264 video.
Firefox is an open source project.
Firefox development is sponsored by corporations (Mozilla Corporation primarily).
Firefox does not include support for h264 video.
...and yes, the webkit you can download from webkit.org includes h264 support. If Mozilla "can't" include H264 in Firefox which has been one of the primary arguments by commenters; I'm failing to see a reason.