Quote Originally Posted by Jojoya View Post
We're not certain what "Obtaining Signature" represents anymore. It used to represent items crafted by a player that had a home world different world from the one the item is being sold on but that's no longer seems to be the case. Our best guess is that it represents items crafted by a character that has since been deleted but we can't be positive. Only SE knows.
It's always been for players that haven't been on that world since the last time the server came up (normally last patch)

That can mean someone from a different world that hasn't been to your world since then, or a character that hasn't logged in since the last update