Being able to assign members into a group and @mention (notify) the entire group at once of a discussion they might want to respond to and participate in is a powerful tool.
I’m surprised more platforms don’t allow group @mentions.
You can assign newcomers to cohorts and invite the entire cohort to introduce themselves without having to tag each person in individually.
You can create groups for experts in specific areas and @mention people in that group when a relevant discussion comes up.
You can create an @mention group for your top members and use it to draw attention to unanswered questions.
If you have this feature (Discourse, Hivebrite, and a few others do), make sure you’re using it. In some clients it’s proving to be a powerful way to sustain a high level of participation.
If you don’t have this feature, it might be worth asking your vendor to work on it.