A discussion function for multiple threads or sub-topics to allow for a clear and logical subdivision of student responses to module sub-topics for a single grade.
A common use would be for generating discussions about several readings within a module. Instructors like to assign a handful of questions and ask students to select 1 or 2 questions to respond to.
If the instructor could create sub-topics ("threads" in Blackboard) under the discussion topic to organize responses, it could reduce endless scrolling, allow for deeper intellectual exchange among students which chose to respond to the same question, and immediately make it clear which questions attracted most attention and which need to be further analyzed in class.
These are the most closely-related ideas -- changing subject lines could help, but it wouldn't fix the organization and endless scrolling problem: