Anyone who has visited YouTube.com in the past four years knows that you can embed video in a web page. But prior to HTML5, there was no standards-based way to do this. Virtually all the video you’ve ever watched “on the web” has been funneled through a third-party plugin — maybe QuickTime, maybe RealPlayer, maybe Flash. (YouTube uses Flash.) These plugins integrate with your browser well enough that you may not even be aware that you’re using them. That is, until you try to watch a video on a platform that doesn’t support that plugin.

HTML5 defines a standard way to embed video in a web page, using a <video> element. Support for the <video> element is still evolving, which is a polite way of saying it doesn’t work yet. At least, it doesn’t work everywhere. But don’t despair! There are alternatives and fallbacks and options galore.

And Mark Pilgrim goes on to explore this fascinating and long-overdue addition to web-developer's armoury. As we have come to expect from Pilgrim, all the technicalities are covered and the essay is written in an easy-to-understand manner with exquisite presentation. The "bible" for video-over-web people everywhere.