It's on my wish list. Right now for the forum in Moodle, you could also subscribe/unsubscribe a certain forum, and track unread messages. It would be great to have a FLAG field (just like outlook) to flag important discussion threads, and be able to track (subscribe) those discussion topics only. It would be especially helpful on the moodle.org/mod/forum/ site, as sometimes there are way too many new threads every day and it's hard to keep track of all the discussion topics..