the origin stems from the need to refer to a non-traditional exchange between two individuals based off of a verb. 'relationship,' based on 'relate,' was rejected bc it has extremely different connotations. 'exchangeship' was rejected bc it sounds lame.
members of an interactionship may be referred to as 'interactioneers,' pioneering new ways that ppl relate, or as 'interactionauts,' (based off of astronauts), bc 'interactionship' sounds a bit like 'spaceship.'
JDH2: Who knows? It exceeds definition. I'd classify it as an interactionship at present.