Cell phone # is used now, the way social security # used to be used, to uniquely identify each person uniquely. Then there's cross-referenced contacts, from each phone, matching names and phone # that all apps upload...
Big Data, Big Brother
Forget privacy in this digital age. While looking online at an item on Crutchfield’s site, I called their customer service for more info. Without asking me any questions, the sales rep knew exactly which item and which webpage I was looking at. I’ve never done business with Crutchfield before - meaning they wouldn’t already have my info in their database. If marketing software can do this, just think what black hats can do. Pretty scary stuff.