> And if a friend had put your name and phone number in their phone, and they synced their contact list with FB and merged the contacts, welcome to the system..

> And if a friend had put your name and phone number in their phone, and they synced their contact list with FB and merged the contacts, welcome to the system... > I wonder if the linking is even necessary, if FBs dark pattern made your friends upload their contact list, they could just infer that since Alice and Bob are your FB friends and they both have your name and number on their uploaded contacts, they can probably associate that number with your FB profile with x% certainty (a higher percentage if your FB friends Cedric, Dave, Emily and Fritz also have the same name and number...). Yeah, my bet's on this. Once, long ago, when I was more trusting, I installed the Facebook app on my phone (back when Android permissions were all or nothing). Facebook slurped up my address book, and I don't even think they ever explicitly asked for permission to do that. About six months to a year ago I noticed these contacts in my FB data dump...and they were connected to all kinds email addresses and phone numbers I never had in my address book. My guess is that if you want to keep Facebook from linking to your personal info from other sources, you need to have zero data overlap (different email, phone, name) and never install any of their apps on any device you own and never share a browser session between Facebook and any other browsing.