Absolute load of bullshit
As usual, this is a conceptual idea, which they haven't really thought through.
Let's say you have a web application and it allows you to upload files, and then share them with other users, in the application. Like, you know, a large number of apps at the moment. If the files resided on this system they've invented, all of the application software now has to be re-written, such that when you grant (or deny) access, it writes the permission data (and the files themselves) somewhere outside the application. The application itself then has no idea of the permissions...unless you duplicate that data elsewhere, or use some sort of API to feed the permissions data in from their service...again requiring a rewrite of your app. If the permissions change, you have to update it both in the application and on their system. This does not "cut down" anything, it's making more fecking work.
So, sorry, but that's absolutely fucking useless, to 99% of people.
By the way: If you want a photo to appear on both Facebook and Twitter, just set the permissions in either to make that asset public. So it's, you know, shareable.