People are generally good, they just tend not to be very vocal about that. Twitter and Facebook, on the other hand, tend to give a megaphone to bad people, allowing them to spread their message wider and louder. That is inherently bad, because thanks to network effect more people would behave in a way they would never allow in real life.

My take away is that, after ten years, we can say that Facebook and Twitter have a negative impact on contemporary society.