Due to the studies I did at university for my dissertation and some exams before that, I have read plenty of material about this kind of subject. For example, these kind of theories have been used to develop "educational" VR tools that should avoid the phenomena of "idleness".
I think it is really interesting also to look into the MUDs behaviour.
If somebody is interested I can recommend the "Bartle Test" (this is the theory behind it
http://www.mud.co.uk/richard/wpm.htm, but I can't find a link to the test) that will help you define what kind of player are you and I would recommend "The Psychology of the Internet" of Patricia Wallace, maybe a bit old in his content more MUd orientated than MMORPG, but still really interesting.
Thanks for posting such material. I think it is really interesting, however I didn't have the time to read it carefully, but I just scanned it.
