Android's implementation of Intents and its sharing menu are probably a better example. I take a photo with the camera app, then hit share. Android automagically knows that Gmail, Messaging, Picasa Uploader, PicSay Pro or any number of image manipulation apps can do something with that image. Reading a cool story in the NPR app? I hit share and can, again, select Gmail or Twitter or whatever else the system recognizes as being able to handle that data type.

I don't think it's a replacement for filesystems, but it is a very powerful way of handling data on a platform as limited as mobile.