Admin notification on new member registration

Hi Jeremy, 

Just wondering how I would get admin notification to work when a new member registers?  Right now in my config.yml I have:
"
Email:
  admin_email: myemailaddress@....com

Member:
  send_frontend_update_notifications: true
"
But this doesn't seem to work (ie: no notification emails are sent) for either a new member registration, or a front end member detail change....
