I'm comfortable sharing my phone number with friends and acquaintances because they're inside my network of trust. Maybe one of them is writing my number on the

I'm comfortable sharing my phone number with friends and acquaintances because they're inside my network of trust. Maybe one of them is writing my number on the walls of bathroom stalls or selling it to spammers, who knows, but I guess you take that risk implicitly whenever you give someone your number. I trust my friends though. I would say most of my friends have no idea that when they install the facebook app they are giving all of their contact info away to facebook. Sure, they click the button to give facebook permissions to "access their contact list", but I don't think most people assume the worst. That just what it takes to participate in the modern culture. So when facebook is making a shadow account using my number and connections with friends, my privacy certainly feels violated. I did not choose to share anything with facebook. I chose to share things with my friends, and they unwittingly shared it with facebook. Giving your phone number to a friend is a reasonable thing to do. Someone wanting to install facebook on their phone is a reasonable thing to do. Facebook tracking connections of people who choose not to use (or participate in any way with) their service by essentially exploiting peoples naivete about its intentions, is not reasonable to me. I can educate the people I know about it, but I doubt I will change anyones minds. Facebook has become a part of our culture, I certainly can't blame anyone for wanting to take part in it. I just wish facebook would leave me out of it and it doesn't.