I believe you are automatically subscribed to all threads which you started as well as all threads in which you post a reply. That is part of the default settings when you create an account at Bleeping Computer. If you don't like those settings, it is up to you to change them. For that matter, I always go through the account settings and change them to suit whenever I join a forum. You may want to do the same.
That said, here's how you can stop receiving email notifications...
a. To Unsubscribe From Threads You Have Already Subscribed To
1. Click on the little down arrow next to your name near the top right corner.
2. Select Content I Follow in the window which appears.
3. You will be taken to a list of all threads that you are subscribed to.
4. Click Toggle Edit Options then check the box indicated by the yellow arrow. That will select all the threads.
5. Click Choose Action then Stop notifying me of updates.
6. Click Update Selected.
Note: You can choose actions actions individually for each thread using the check boxes shown.
a. To Unsubscribe From Future Threads
1. Click the down arrow next to your name but this time, select My Settings.
2. You will be taken to your Profile Settings page.
3. Select Notification Options from the left pane.
4. Go through the notification settings in the right pane and change them to suit.
5. When done, scroll down and click the Save Changes button.
6. You can visit these settings whenever you want.