If you hover over My Account at the top of the page, go to Settings and then Notifications, you can switch them on or off for various different events. On individual articles (not forum topics), you can also choose to subscribe to all new posts after you leave a comment by ticking “Notify me of followup comments via e-mail”.
Hopefully that answers your question. I’ll close this topic now because it is in the wrong section. I suggest you use the site development section if you need further help.