Cohorts in Moodle allow users to be categorized and allocated across courses. Cohorts provide benefits like corporate confidentiality by separating client groups and easier enrollment. Cohorts are collections of users that can be assigned across a system or course categories. The key differences are that cohorts can be allocated to multiple courses while groups and groupings are only within a single course. Coordinators and administrators can create and manage cohorts to customize what users can access.