Breaking students into groups allows teachers to manage students in smaller numbers. Putting students into groups permits them to interact on a smaller scale. The concepts of groups can be applied to most activities around a Moodle course.
One of the downsides to groups is the tedious business of placing students into groups they will be happy with. There are the usual requests for a student to be grouped with a friend. There is also the hassle of accommodating late starters or reorganizing groups after a student "drops out".
The Group selection module enables students to "enroll" in groups of their own. The module works with the group functionality that is already baked into Moodle, and works well.
The Group ...