good explanation how to use ffmpeg for webm

http://maketecheasier.com/encode-webm-videos-for-youtube-in-linux/2011/01/26

HOWTO: Install and use the latest FFmpeg and x264 for ubuntu

http://ubuntuforums.org/showthread.php?t=786095

powerfull webm converter

I have to convert my videos on my website, cause vimeo want's cash for 'mobile playback' - yawn.
so http://www.transcoder.org/ could be the solution with http://videojs.com/ .
So lets see ...