"Sociologists have long known and talked about “two kinds of social networks,” and refer to them alternatively as primary and secondary ties, or weak and strong ties."

Facebook did render the word "friend" meaningless. Good point.

At the end of the day, Mark Zuckerberg didn't need $16 billion more in his pocket.

What this person is getting at is that our communication needs change depending on the type of tie. An engagement or a new baby may well be best announced to a large group of weaker ties, whereas most day-to-day conversation is carried out with our smaller, primary social networks. (Yep, Facebook newsfeed versus WhatsApp). This is not an either/or statement. Both types of conversations and interactions are primal, important and central to human social interaction.

Facebook’s key problem for many people has been what academics sometimes call “context-collapse,” which is the sense that Facebook sometimes feels like an extended Thanksgiving dinner where everyone you have ever known is at the table. This is an identity-constraining environment as it’s hard to know how to address such a large crowd at the same time. People have been grappling with this for a long time and have come up with a variety of solutions, including fleeing to Twitter & Instagram and, yes, Whatsapp.

Social scientists have long been trying to communicate this to technology companies: it is normal, natural and healthy to have different communication needs at different levels of one’s social network. One wonders if, early on, Mark Zuckerberg had listened to social scientists rather than declaring “having two identities for yourself is an example of a lack of integrity”, would he now have $16 billion more in his pocket?

isn't that part of the glory of the internet? at least the earlier internet? a new identity. 

Yes. And the post-Facebook Internet glory seems to be that way too.