@dave, I spend far more time at ATP than at my regular email address, so I would rather not want to be notified there about any tree-mail. Is there a feature that enables me to do it?
Certainly. Go to your profile (click on the person in the top-left of the page) then click on "Change your site preferences" and you'll see the option to "Private message e-mail notification?" - set that to No and then save your changes.