Teacher: What is the purpose of the "Force students to follow the group" option?
A teacher can find this option via

The Information System Teacher [course selection] (Students) Discussion forum

In the "Discussion forum of courses (and their seminar groups) taught this term" section, click on the name of the course-related discussion forum. Next to the list of threads, under the tooltip icon, you can find a menu and the option "Force students to follow the group", which will add the discussion forum to students' followed discussion forums. This will make it easier for them to access this course-related discussion forum.

1 In the menu under the tooltip icon, you will find an option to force a specific course-related discussion forum on students.

Tip: Only topic-based course-related discussion forums can be forced The function can be used exclusively for course-related topic-based discussion forums. General course-related discussion forums cannot be forced on students.