I think the web-based desktop idea is the next big thing on the net. Backpack is a Rails app that is moving us in that direction. The problem I’m having is that all these are companies which want control of your data. They want you to pay for their service. There’s nothing wrong with that for some people but I want complete control. I would like a web app that I can install on whatever webserver I want and take my files and my customized desktop to another host if I want. I just pay for my normal hosting and that’s it. This leads me into thinking that this desktop webapp I’m going to try to get started writing will need to be an open source project. There are ways to make money off it in the long run like these companies are trying to do but that’s not the overall goal of the project. That would be a side project that would use the open desktop and build a business around deploying it for users.
Then it’s a matter of understanding how to interface with different webapps via RSS, XMLRPC, SOAP, or something like that. The first line of business after the desktop and windowing is working is creating an open source filesystem webapp to bundle with the desktop. That way you can either use the bundled filesystem or you can use another webapp to store your files. Personally, I want full control over my data so I’d host my filesystem on the same server as the desktop.