Tony; I've written a lot about Elgg; ever since we used it to support several communities of practice in the healthcare field.

Elgg's main premise is that the learner is the centre of everything and decides what is important. There are no course or program boxes that learners have to "go in". Elgg is a good tool for CoP's because you can have "frends". Elgg is not a course management system, because there are no courses. For educational settings, I would suggest Elgg for informal learning and giving a sense of continuity outside the construct of the course and Moodle (which integrates well) for the individual courses.

We can discuss this at TK2007 if you like.

BTW, a lot of people are turned off Elgg until they actually see it action. Not sure why.