Opt out of ATT settings which monitor your activity:
Go to
https://att.com and log in with your account.
Click "Profile" in the upper-right of the second ribbon.
Click "Privacy Choices" on the right of the new, third ribbon.
Change all options to "off." (on mobile, swipe/scroll the screen right to see all options that can be disabled)
Save your changes.
These settings are enabled by default and enable AT&T to know more about you than you'd probably like.