I wonder whether there were any negative repercussions for the postman? I'd be surprised if there isn't a policy against personally contacting mail recipients.

Surely it'd be some sort of data protection violation for him to have used the data printed on the envelope to find the guy on Facebook and send him a personal message?

Or is ad-hoc sleuthing allowed to a reasonable extent to ensure delivery of mail?

This is cool though, maybe I'm just boring. :)