Forums are an effective way of coordinating student discussion. Forums serve a different purpose than site Activity, as forums allow users to create and respond to posts within a given topic. BuddyPress does not enable forums by default, but allows us to create both a general forum for all site users as well as group specific forums.
To install a forum, visit the WordPress dashboard, hover over BuddyPress in the left sidebar and choose Forums. From the Forums screen we are able to install both Forums for Groups and Site Wide Forums by clicking the blue Install Group Forums or Install Site Wide Forums button.
While it is possible to enable group and sitewide forums simultaneously, the distinction to site users is not clear, causing the experience for students to be confusing. I would recommend selecting only the type of forum that best meets your needs rather than installing both.
Group forums will give the members of a group access to a separate discussion forum. Only group members will have access to post to a group forum. Forums can be useful when groups of students are coordinating information, such as a research project, which could otherwise be lost in a frequently updated activity stream.