The Blurring Line Between PC and Web
The NYTimes has a feature about software development systems that move the Web offline and desktop applications online, with a focus on Adobe Air, which will be released tomorrow. The article has quotes from the developer behind Microsoft's Silverlight (he was a colleague at Macromedia of Adobe's Air guy), and from the head of the Mozilla Foundation about their online/offline offering, Prism.
The problem with AIR is that it requires "porting". A website won't just work in AIR, and once it's been ported, it will no longer work as a regular real website, as it'll have dependencies on Adobe AIR. This effectively means that if you as a developer want the best of both worlds, you'll need to maintain two version of your application.
The approach Mozilla is taking with Prism on the other hand (which is also being taken with Bubbles and Fluid, with standardization between these in the early stages of being talked about), is to make available small features which allows a real website to gain some properties on the level of a desktop application when run from Prism, without stopping to work as a website. This is the progressive enhancement approach, which helps keep the web open (any browser can continue to run the application). It's very important for developers to realize this distinction, less the web gets locked into a proprietary realm. (both Microsoft and Adobe would love nothing better than to be the sole gatekeeper to this realm.)