You've subscribed to several threads inadvertently.
To unsubscribe, either:
1. Visit the link in the email or find the thread in the forum and deselect 'Email me when someone replies...'
2. Visit your user profile page and uncheck 'Enable email tracking' (This will stop all email so if you want to subscribe to a thread, you'll have to check it again to make it work.
I think I got that right, let me know if you have trouble with it.
When you begin a thread or reply to one, you'll be automatically subscribed to it. Click the "Email subscription enabled" button at the top of the discussion list to unsubscribe.
