Right now I'd like to focus on one post, Like Playing Monopoly With Squatters, which brought to mind a much earlier thread on RPG.net, [Theory] Show, don't tell. A lot of the people on that thread are talking past each other unfortunately but what connects it to Zak's post is the idea of "irony" or distance that I brought up.
What Zak points to is, in my opinion, something that really doesn't go away, ever, in spite of his suggestion that there are styles of play that try to minimize it. I wonder if this is what Chris Lehrich was referring to when he said he didn't really think that people completely immersed. (Or something like that: I don't want to put words in his mouth. It was something about how he had a theory regarding what "immersive" players were "really doing", but he never elaborated. I can imagine it was related to ritual and the way it deals with ambiguity.)
There are a lot of dimensions to this. Mainly though, Zak's post brings back to me why, in an RPG, I often find it useful to have some distance from my character. For example I think there's fun to be had in a horror game if my character dies in an interesting way. This is entirely different from being a good sport. It's basically enjoying the narrative that arises from play.
But even in acknowledging this sort of enjoyment, I get very little out of controlling the narrative. Similarly I can get a kick out of "portraying" or "expressing" a character, and having the other players at the table react/assist with that activity. I realize it's not a fully "immersive" state. Yet it's still distinct from the highly "out of character" thought processes that seem to be implied by
a) Games that entail player-improvisation in the service of "driving for conflict" (prime example: The Mountain Witch), or
b) Games that entail player manipulation of abstract mechanics in the service of achieving player-character goals (prime example: Dogs in the Vineyard).
c) Games that entail the use of abstract mechanics to "shape" and therefore "direct" subsequent roleplaying (prime example: PTA).