Presumably something similar to the Gmail "Undo Send" example? Time limited reversal (in this case specified by user preference) to give you at least some amount of time to reverse your actions before they become permanent.
It's 5/10/20/30 seconds for an email, which seems like a good fit for that use case. Perhaps a Facebook profile delete or mail delete might be more like a 5 min/1 hour/1 day option set, since it doesn't interfere with the primary purpose (i.e. I wouldn't want to wait an hour for all my emails to get sent, but I might be OK waiting an hour for them to actually delete).
It's 5/10/20/30 seconds for an email, which seems like a good fit for that use case. Perhaps a Facebook profile delete or mail delete might be more like a 5 min/1 hour/1 day option set, since it doesn't interfere with the primary purpose (i.e. I wouldn't want to wait an hour for all my emails to get sent, but I might be OK waiting an hour for them to actually delete).