You know that Apple don't like Flash anymore and doesn't include it in the iPad. Personally, I never liked Flash in the first place because it needs a non-standard plugin in the browser, and I can never be sure that the visitor has the most recent version of that plugin. Same goes to Microsoft Silverlight; I know that it's awesome and one can do incredible cool things with that technology, nevertheless, it needs a plugin, so I would never use it for public websites / webapps.

HTML5 seems to be the way to go. And Apple just published a demo what HTML5 can do.

Note, that demo only runs in the Safari browser. Most other browsers should be able to do the same, but I think Apple want to show how nice all that stuff works on the iPad and therefore made it Safari only.

Here is the demo: http://www.apple.com/html5/