In your user cp there is an option somewhere to autmatically subscribe to all the threads you reply too. Go to: User cp > edit options > Messaging and notification > default thread subscription mode > click in the drop down box and select which option you want > save changes. Then go to quick links and any threads you reply to after that will be in your subscriptions. There will also be a blue tick next to a thread that you have contributed to. Failing that visit your profile and click on the 'find all posts/threads' by this user option.
