Google is pushing WebM as a video format for HTML5.
From the Wired article:
"With its new player, Adobe is responding to their developers’ wishes for solutions that play well on the open web. It comes on the heels of last week’s release from Adobe, which lets artists using Illustrator export their drawings as HTML5 Canvas, and its earlier pack of HTML5 tools for Dreamweaver.
HTML5 video adoption among browsers has gone tremendously so far — Chrome, Firefox, Safari and Opera all support native video, and baked-in support is coming to Internet Explorer 9 next year. But it’s still a bit of a mess, with different browsers supporting different formats. So developers posting HTML5 video still need to encode their files in at least two of the three major formats — the widely-used H.264, the newer WebM or the older Ogg Theora — to guarantee all HTML5 capable browsers will be able to see their videos."