Apple Thoughts: YouTube Dropping Support for Older Browsers

"YouTube is dropping support for certain older browsers, most notably Internet Explorer 6 for Windows. But reader Mike Lemon discovered and alerted us that the last release of Firefox for Mac OS X 10.3.9 Panther - version 2.0.0.20 - will also be dropped from supported browsers."

You can find out more on the YouTube FAQ page, but basically they are not supporting browsers that are older than Firefox 3+, Chrome 4+, IE 7+ and Safari 3+. This doesn't mean you can go to YouTube if you have one of those older browsers, it just means that some of the improvements they are making won't be engineered to work in the older stuff. Support officially stops on March 13th, 2010.