Welcome to AA!
Click on "User CP" in the blue bar near the top of the screen. Go down the list on the left side and see "Settings and Options". Under that heading, click "edit options". In the second box, "Messaging and Notification", find "Default Thread Subscription Mode" and use the drop-down box to select "no email notification" or "do not subscribe".
I turned off my email notifications too but I still subscribe to the threads I post in. Subscribing will display a little check mark on the index page of threads you have posted in and I find that helpful.