From what I understand CPNI is used to sell you other att products... this web link only opts you out of CPNI shares within att.
quote: The AT&T family of companies includes those AT&T companies that provide communications-related products and/or services, including the AT&T local and long distance companies, AT&T Corp., AT&T Long Distance, AT&T Internet Services, AT&T Mobility and other subsidiaries of affiliates of ATT Inc. that provide, design, market, or sell these products and/or services.