Well, I’ve thrown up a page at nLab for quantum channels since the only quantum-related pages over there (so far) were mostly field theory stuff. It already got a community edit to make it look better (!) which is cool. Now I just have to convince Bob Coecke and the other categorical people in quantum information-related fields to start using it (John Baez already uses it). I figure this might be a good way to work my way through my Birkhoff theorem stuff with some assistance.