If your friends have your details in their address books and have connected the mobile app to it, then FB has your info already. Just because you can't see it on your profile doesn't mean the data is not on their systems.

I know that. And there's no skipping it unless you are willing to go to the mountains and live off the grid (until the day they come looking for you :-) ), or unfriend everyone.

I just try to share the least amount possible.

I'm glad you do but I suspect most people don't. It takes a mental leap to realise that other people can now (unknowingly) do things that expose your information to parties you're trying to avoid sharing with. Even writing it now I feel like it's obvious but people I speak to really don't understand how things work.

Couldn't agree more. I was off Viber, or WhatsApp for about 3 months. Had closed the accounts after installing and I had moved to TextSecure and Telegram. I was successful in convincing some friends to join Telegram (they were still on Viber/Whatsapp) but I had 0 friends on TextSecure. Finally Telegram friends uninstalled it. As I was missing a lot of messages, fun, and info about common friends I came back to WhatsApp and Viber and that made me sad. I tried to explain what Facebook buying WhatsApp meant, it didn't work. They don't give a damn and I talking about intelligent technocrats who passed from the best tech schools in the country and are in the best s/w jobs. Privacy is a cultural thing.