You have your Thread Subscription set to Automatically Subscribe without Notification.
That means any thread you post in will send you a notification of all new posts in that thread.
To change this:
Click
Settings on the top right of any AW forum window.
Scroll down to the section labeled
My Settings in the sidebar on the left.
Click
General Settings.
Scroll down to the section labeled
Messaging & Notification in the central section.
Under the
Default Thread Subscription Mode heading, there's a pull down menu.
This setting determines your default automatic setting for Thread Subscriptions.
I generally suggest people use
Do Not Subscribe, and then subscribe to the threads they specifically want to have notifications for.
After you select an option, scroll all the way to the bottom, and click
Save Changes.
See:
FAQ: Everything You Wanted to Know About Thread Subscriptions