I was wondering this also.
The only threads that show up in the user CP are ones I've subscribed to (the ones I subscribe too tend to be ongoing "group" threads vs the every day question threads), is there a check box we have to tick once we've commented on a "every day" thread to just "track" it, or do we have to subscribe to each thread we comment on to be able to do that?
For example a different forum I go on, automatically notifies me of new posts with out actually having to subscribe.