The point is that today you are always online on your phone. Whatsapp, Viber or Messenger always work. No need to log onto a mainframe and type forum.

I feel that the point made is a good one. Given that we can share what we want directly via instant messengers that everyone has "turned on" all the time, value proposition of Facebook drops dramatically. Anything you want to share you can share directly and immediately get it to whoever you want to see it.