jimhenley's post in the Whither Theory? thread/This is something I think is stunningly important and under-examined in RPG theory thus far, so I want to open it big-time here. Note that there is a discussion of something like this at The 20x20 Room, 'Missing Link' thread.
I think it's also important to scan all the way back to the origins of D&D and Runequest and Petal Throne and so on, so anyone who has strong information about that stuff, please pile in. Links very welcome too.
