in its most basic form, needs to keep track of the most recent post each user has read in each thread, and display how many unread posts there are in a given thread.
for usability there could be an option to subscribe or unsubscribe from a given thread, "mark as unread" back to a given point, mute threads or forums etc. maybe there could be a "notifications" page that shows you all unread posts on threads you are subscribed to.
this needs to also support being notified of new threads somehow.
assigned to: no one
fossil branch: n/a