There is a format war in HTML5 consisting of open standards such as Ogg Vorbis and Ogg Theora versus proprietary MPEG4 formats such as H.264, pushed heavily by Apple. This may not mean much to you, but it does affect your ability to view certain web content.

All streaming content on this site requires an HTML5 compliant browser with support for open standards. The latest versions of Google Chrome, Mozilla Firefox, and Opera are all supported.

Internet Explorer users can add support for these functions by downloading an add-on called Google Chrome Frame. At least I think, as I do not have a Windows computer to test this thing on.

Apple Safari users are completely screwed. Get Chrome or Firefox and get on with your life. Apple is the devil in this format war.

For a standalone player for Theora video content, I'd recommend VLC, a cross-platform, open source, all-format video player.

For more information on the Ogg projects including Theora, Vorbis, and FLAC, visit http://www.xiph.org/