[nitinagg]

So dropbox always deduped data at it’s backend without any such user facing change. How is this better than that?

[sanderjd]

This is unrelated to that. It isn't about de-duping data, it's about symbolic links ("shortcuts") vs. hard links ("multi-parenting"). You can still make copies of files as usual, and the content can be de-duped (or not) transparently to users.