Learning Communities are real groups. They are not only digital message board. They can be companies, colleges, academic departments, social organizations, professional associations, high schools, sports teams -- literally any group.

From Wikipedia: A learning community is a group of people who share common emotions, values or beliefs, are actively engaged in learning together from each other, and by habituation. Such communities have become the template for a cohort-based, interdisciplinary approach to higher education. This may be based on an advanced kind of educational or "pedagogical" design.

People join learning communities for three reasons:
1) To get access to opportunities.
2) To meet people.
3) To learn.