The Irony of iPad: A Great Day For Open Technologies
I actually tweeted about this exact thing after catching up to the announcement:  Despite iPad propriety, higher res + HTML5 make web apps   
  much more relevant and far cheaper/faster to develop & iterate.

I think this is absolutely awesome for web apps. The only thing that's missing is the ability to sell "icons" on the app store that merely subscribe one to a web app and stick the link on their home screen. This would meld the ease of development and deployment of web apps with the ease of payment processing the app store provides. I don't see this ever happening because Apple couldn't control the ability to review subsequent changes before they were live, but it's a nice dream.