Web start has to be one of the best web technologies that almost no one ever heard of. It had most of the benefits of the web for LOB apps, and most consumer apps are probably better off not being web based in the first place.
Right, that too. For example, the amount of work that every serious web app puts into implementing some kind of hierarchical system for storing, naming and accessing objects and then allowing users to share them with each other is astonishing. If only there was a way to have the operating system provide some kind of similar abstraction to the users!