Re: "...an indefinite number of things that likely have no direct bearing on learning like use of nouns, short sentences, words beginning with 'A' and so on. Hard to know where to stop."

Interesting...

As an educator of English as a Second Language, I had to single out the statement above.  I would need more time to comment on it.

Regarding the sets/subsets mentioned, I find that as (human) agents with the capacity to consciously and unconsciously (subconsciously?) make decisions, we so choose our depth/shallowness as we maintain an online presence.

As I read (more, and more, and more...) some of the literature for 802, I pause and reflect on how my own learners must 'feel' when they willingly choose to search for knowledge in our online tasks; how they choose to reflect on what worked/what didn't; and how they react toward the experience. 

As agents, we belong to the social world where feelings - more often than not - shape and guide our actions. Therefore, the emotional presence may be on a category of its own (perhaps, a new topic for doctoral research with a post-constructivist underpinning?).

I'd not thought about ESL. On reflection, there is probably nothing that couldn't potentially make a difference to some learners, sometimes. It ain't what you do, it's the way that you do it.

I agree - the emotional aspect is crucial in all learning (at least from an individual's perspective, even if it is not made visible in a discussion) and, sometimes, is by far the most significant part. I also think that it could qualify as a presence in a CoI, by the implicit definition of 'presence' in the COI model, because it is something that can be discoverable in a learning dialogue. Perhaps there's a more general 'affective presence' that might encompass this, and perhaps that also encompasses teaching and social presence, and maybe agency. Or maybe we could narrow it down to a more neutral 'sentiment presence' (which clarifies that it is about what is expressed rather than what is felt).

The more I think on it, though, the more I think we are in the realm of Wittgensteinian language games and family resemblances. There are countless facets and dimensions that may be significant or insignificant in different learning contexts, of which social, teaching and cognitive presence are only a few, any one of which might be missing (well - I am not sure about teaching presence, in its loosest, distributed cognition sense, but if we are using it that way then it leads to a tautology and tells us nothing). This is a lot like trying to define what we mean by 'game' - any definition we can conceivably come up with will admit to exceptions. There is and can be no common feature set that describes all games, nor all communities of inquiry, but we all generally recognize one when we see one. And, of course, it is very valuable to have discussions about the definitions that we do come up with, even though none can actually be truly definitional.

This conversation is, incidentally, a nice example of a CoI!

For me, the real value of a model is that it provides a useful conceptual vocabulary and generates this kind of discussion. Humans seem to like trinities, which may be part of the appeal of the COI model.

Your post has litefd the level of debate
- Deacon