Valve Software has a distribution platform called Steam. It’s very simple, and very nice. You buy a game through Steam, and download and install it. When you get a new computer, you sign into steam, and re-install all your games. Don’t play a game much anymore? Delete it, you can always go back and get it. No CDs, no need to back stuff up, etc.
Dropbox is a relative new service that let’s me have a folder on my computer at work, and at home. I can put a PDF I want to read later in the folder from work, and it automatically uploads it, and my home computer automatically downloads it. Dropbox also lets me share folders and is starting to integrate with other services.
Both of these services have other features that are nice, but what I’d like to see is something that would basically let me buy a new computer (or reformat my current one in the wake of a virus or spyware or disk failure), and just go through and download the things I want on it. It would also keep things in sync, maintain checkpoints and versions. So my photos are in a folder, but they’re also on Flickr. Changing it in one place changes it in another. My music is there, and can be streamed when I’m at a friends house. The possibilities are pretty open.
It’s basically the benefits of an X-windows remote environment I guess, though that could even be integrated if it had a thin client into a virtualized box you paid by the hour for… I’ve seen lots of pieces of this out there, but nobody that’s really working on the basic central component.