You might have accidentally clicked something that meant you would get a notification everytime someone posted on a thread you had posted on.. This should get rid of the notifications:
1. Click 'profile'.. in red up the top
2. Click 'preferences'
3. Find the option that says 'Always notify me of replies :
Sends an e-mail when someone replies to a topic you have posted in. This can be changed whenever you post'.. and select 'No'
This should stop the notifications.