One advantage of node that wasn't mentioned is the ability to share server side and client side code. Avoiding discrepancies in the same form validation written in two different languages can often be more important than performance gains in server applications.
I think facebook definitely has beneficial uses (reconnecting with old friends, arranging events etc). But I feel like a lot of people are addicted to it and allow it to get in the way of having real, face-to-face interactions. Eg people who can't have a dinner conversation without looking down every 10 seconds to check their wall. It's a kinda scary trend that seems to be becoming increasingly prevalent in the younger generations.