I installed Firefox 3.5 on my Windows boxes, but not on my Linux boxes because Mozilla.org does not offer 64-bit Linux builds. One of the features of Firefox 3.5 is the support of the Ogg Theora video file format, which is the format of all of the screencasts I posted on this blog.
I use Ogg Theora because it is the native encoding format of the recordMyDesktop screen capture utility for Gnome. Since this format was not natively supported on Windows or Max OS X, every time I post one of my screencasts/demos, I have to put in a disclaimer—"Linuxy format, download VLC to view".
Not any more! Now you can view it directly in Firefox 3.5:
Sorry, your browser does not support the HTML 5 <video> tag. Get one that does.
(The video is from an old blog entry of mine showing JavaFX 1.0 playing Ogg Theora video files on Linux.)