You're getting sidetracked by the word "private" instead of looking at the contextual meaning of the conversation people are having:
When grandparent poster (asim) wrote: >"and now people need to go back to something more real and private."
asim meant "private"=="less-visible-more-intimate-group".
You're talking about "private"=="walled-garden".
The threeseed's reply of "So I think public networks still seem far from dead" is responding to asim's usage of "private" and not yours.
I'm saying only your friends on Facebook will see your posts, so it is private, unlike twitter where the whole world will see them. And you can create groups if you want to have even more private discussions.
Twitter, LinkedIn are walled gardens, but public ones. Facebook is a private walled garden.
Compare it to a WhatsApp group: there one defines exactly the people who should see a given message. "Friends" becomes mixed between "true" friends, neighbors, colleagues, ... people you once we're closer with but passed ways to some degree, ... after a while it's semi-public at least unless you have a strict (un-)friending policy. For average users the visibility is also hard to understand.
