The next generation of HTML language for web page development and web-based applications (beyond HTML4 and XHTML) is here. HTML5 is going to dominate the web someday soon. The iPad early success (300,000 devices sold in the launching week-end) accelerates HTML5 popularity.
This future web standard allow programmers to build sophisticated web sites that behave more like downloaded applications.
HTML5 has many advantages:
HTML5 does not require developers to build sites in a whole new way.
The list of HTML5/iPad-compatible sites increases everyday. Here is an HTML5 projects gallery.
The most notable example is Google, which is using HTML5 for its mobile version of Gmail, that works both on Android and iPhone/iPad. This also allows Google to avoid Apple's approval process, since the application is accessed via the web, and the Apple App Store.