Hey - using the Subscriptions plugin.
My client uses the forums as a communication platform with his clients. Each forum and its children regards one project, and a client should be notified of activity on all topics within this form and its children.
My client swears that when he used the site more actively (may have been two years ago, even) that he had a button he could use on the backend to quickly subscribe a user in such a way. I don't see anything. Does that sound like something that might have existed at one point?