just announced that it will begin supporting HTML5 video players this evening across many of the videos on the site. The feature isn't live yet but is expected to be within the next hour or two. If this test goes live site-wide, it will be a good thing for the web.YouTube
An HTML5 video player will allow videos to be viewed without Adobe's Flashplayer plug-in, videos will load faster and developers will be able to build all kinds of other intriguing features into a media delivery scheme based on the next version of HTML.
For now users will need to sign-up the HTML5 preview on Test Tube and they'll need to be using either Chrome, Safari or the Chrome frame in IE.
The biggest benefit of HTML5 support is that it frees users from the need to use proprietary plug-ins like Flash player or Microsoft's Silverlight by using a simple bit of code to render video. (Note this caveat regarding the lack of codec consensus, however.) If you've used Google's Chrome much, you've probably seen how often Flash player crashes in that browser. Firefox doesn't deal with Flash well, either.
HTML5 is being edited by Ian Hickson of Google and David Hyatt of Apple. Expect to see Google and Apple support this new standard all the more in the future so that those companies and others can build a web that looks more like Gmail on an iPhone than it does like a Flash landing page from the last decade.
For more details, see these 3 great HTML5 demonstration videos we highlighted previously.
Update: YouTube also just announced a new design of its Flash-based video player and watch pages.