On many forums you can tick a box so you will get emailed when someone post a reply on a topic, you can tick the box when you write a reply.
Here on Armor Games I would enjoy to see such a system, it will make it more enjoyable to be more active on the forums, atleast for me.
Besides that you could also make a notification system of some kind, like on Facebook, so when someone have wrote a reply on a Topic or something, there will come a (1) like on Facebook.
