Just read article in depth and found two more significant "features". First one - database build by AT&T can identify if target individual uses multiple phones (So if say I was engineer Joe and wanted to get sell private cell number(s) for Angelina Jolie how much would you pay?). Second - they can identify if you switched to a new number. Even if you threw out your phone. (So speaking of numbers, how much would you pay for a yearly subscription previously offered 'product'). Seriously if AT&T doing this, there is no reason to believe that other providers do not.