OPs have a list of the threads they started in the "Transmissions" section of their profile.
Unless someone quotes a user's reply, or tags them into their post, there's no way of easily checking back on post/news/etc responses made on posts. Even then, the "bell" notifications list only shows the last ten or so.
AWA devs: Can you add a list of all reply posts that a user has made?
i second this, and while you're on it add a proper search as well as a bookmark function, this forums software lacks all the essentials forums should have and isn't very convenient, not to say utter trash