First, remove any threads which you don't want notifications for on this page:
https://www.sportscardclub.com/watched/threads/all
Then, go to your preferences (you can get there by clicking your name in the top right), and un-click the "Automatically Watch Threads" box.
Or, if you just don't want the site to email you at all, just go in the privacy page and unclick the "Receive Site Mailings"
https://www.sportscardclub.com/account/privacy
It might take up to 24 hours or so for all the emails to flush out of the system.
https://www.sportscardclub.com/watched/threads/all
Then, go to your preferences (you can get there by clicking your name in the top right), and un-click the "Automatically Watch Threads" box.
Or, if you just don't want the site to email you at all, just go in the privacy page and unclick the "Receive Site Mailings"
https://www.sportscardclub.com/account/privacy
It might take up to 24 hours or so for all the emails to flush out of the system.