"""Coming from the opposite side, I wonder if there's an "anti-hoarding" disorder; feeling that most things (physical or virtual) in one's possession is a liability, a weight that would be better off discarded unless they are absolutely necessary."""

There sure is one -- and the minimalist trend has a little to do with that tendency, but it's something much rarer than hoarding.

A lot of people do the "anti-hoarding" thing with emotions, memories, friendships and relationships, though, just letting them slip through without affecting them.

Coping mechanisms, if I ever saw one...