I dont konw if anyone else have had this issue... I was getting a lot of notification mails, this is how you avoid that:

Click "Profile" (top) --> "Preferances" (on the right) --> a bit down you will see "Always notify me of replies :" set this to no and save.

Lastly, to stop watching old topics:
Click "Profile" (top) --> "Topic being watched" (on the right) --> mark all, click "Stop watching the selected topics"

I wish there was a way for me to deactivate this, but I have not been able to find one yet.

And also, uncheck the box on the bottom that says "Notify me when a reply is posted" it is under the "Options" menu.

I am working to find out how I can uncheck this as default. Sorry for the inconvenience!