I understand why this is happening; application developers want to regain control of the stack and of content sales - Facebook especially wants to bring its app infrastructure with micropayments to iPhone without giving Apple its cut.

However, web apps were tried before - the original iPhone, for example - and were overwhelmingly underused and rejected by users. Has that changed? Possibly, but until we see the next crop of webapps we may not know. Personally, I feel that there is a certain irrational preference for having an app installed on your device, where it won't change or update automatically and will be accessible offline (even if you can't do anything useful with it).

Having said that, web apps have expanded and done quite well in the PC world - the idea of a native Facebook desktop client is laughable, and I'd guess that most average users use a web app for email.

It'll be interesting to see how this battle goes.