Hi there,
I'm slow but have a lot on and my brain is full to bursting with topics other than this one...
I'm with Mark. C and B.
I want to say that it's all in the design - also you can never guarantee anything and social presence really won't do anything for some students, just be a bind. On the design angle I've been part of designing a course in spiritual formation itself that was emphasising personal journey so did not have much online interaction at all (minimum really) but majored on good video material from the subject matter expert seeking to emulate something of a sense of speaking with a spiritual director and required frequent journals frequently commented on so another layer of spiritual direction happened with the tutor. That seemed to be plenty of social presence for most people.
Rosemary