Firefox 4 Youtube HTML5

Okay, now that Firefox 4 is released and has been downloaded 40 million times, I want all Firefox users to do the following:

  1. Go to
  2. Click on “Join the HTML5 Trial

Most Youtube videos you watch will be served in WebM format with HTML5 markup, instead of Flash.

Sidenote: Before you go thinking Firefox 4 is the first version of Firefox to support HTML5 video, it should be noted the HTML5 doesn’t specify video codec. Firefox has had support for HTML5 video since version 3.5.