Calling is absolutely a better substitute for maintaining contact with friends than Facebook. Actual real-life facetime is even better. A lot more information can be conveyed in a real conversation.

I can understand that Facebook might be a good way to keep in touch with acquaintances, but if you use it to keep in touch with friends that's what they'll soon become: mere acquaintances. Exchanging a few typed words every now and than isn't enough.

Also: nice ad hominem on the "not very many", please try to keep it civil on hackernews.