Nowadays your Facebook account gives much more opportunities to other people to stay in touch with you than your phone number.
When I meet new people, I totally don't mind to give them a link and then keep talking online.
But if they ask me about my phone number (for example, for whatsapp), I always get very confused. I cannot explain it! Facebook tells and shows much more about me than my phone number for sure, but to me it feels like they to look at my private area, inside of my underwear.
I know it sounds weird, but what can I do? I cannot control it! >_<