Hey, There is probably some how to do this I just haven't found it yet. Well, because the forums are so busy, the threads you post in get lost easily and its hard to keep track of! You can find out all the threads you have posted in by going to the user profile, but as far as I know to get to your user profile you need to find a thread you have posted in a click on your username. It would be good that if where it says 'Welcome, username' in the top right corner, if username was linked to your profile. Just a suggestion. Cheers.
You can also look in your userCP which will list all of the threads you've posted in with new posts...that is assuming you have the default subscription levels set here. If not then go into userCP > Edit Options > Messaging & Notification > Default Thread Subscription Mode And set it to your desired preference. (no email notification I think is default) Also, at the bottom of the main index under "whats going on" there is a list of online users...you are the first one listed.