> Are many people you know actually going exclusively to facebook as their sole communication method Yes. Absolutely. People communicate via Facebook Messenger

> Are many people you know actually going exclusively to facebook as their sole communication method Yes. Absolutely. People communicate via Facebook Messenger instead of SMS or the likes of WhatsApp. They organise social events using Facebook. Announce weddings and divorces, births of children, new jobs. Everything via Facebook. You're clearly not a Facebook user (or not a regular user) otherwise you would know the extent to which people are using it. And most people really don't care about Facebook privacy issues to any significant degree. It's more convenient to use Facebook and have compromised privacy than not to use Facebook for many.