One possible application of this data migration is to learn what the users are doing, predict their future needs based on current actions and past actions, and optimize data placement accordingly. Consider a user that leaves their office at 5pm and drives back home, reaching home an hour later. It would be desirable if by the time the user reached home, all the important data they need access to was migrated or copied over to their home file server; that way the user can resume work on important files once they reached home, without having to spend time copying data by hand or trying to access it over remote slow networks. Another application of this data mobility is that such a system should know when a user has purchased an airline ticket to attend, say, an international conference. By the time the user arrives at their hotel room (or even the airport, or even inside the plane in transit), the user's email will have migrated automatically and safely so it can be accessed locally from wherever the user is.