Towards a narrowed network, really?
I believe that people are simply introducing more layers to their network. Within their network they will always have friends and family but also people they met at a conference or a person they do not know but whom they are interested to follow because interesting to them.
We are reorganizing our networks. We are living the same phenomena as when mailboxes introduced folders. With each level we have different interactions. Having everybody following you for the picture you are posting about your kid does not make any sense. Only your family and friends would be interested about it. Having people who you do not know follow you for your writing has a different purpose.
We are organizing ourselves. Sometimes we are claiming this as being privacy of data, this is simply maturity of the network. Indeed you will invite only your best friends to stop by at any time. Other friends will come home by invitation. Others will come exceptionally. Others will only be met at some events or during parties happening at some other friend’s house. THIS IS THE SAME! We are always making a big deal about what is happening in the online world but in reality, nothing different is happening than what would happen in life. Online is a simple duplication of our real lives. You want to know what will happen next year, think about your personal relationships and how you manage them and you will know.
Also, over the time, some people we met disappear from our circle, others become closer, others get introduced. This is what is happening to the network right now. We are not unfriending people, we are just cleaning our address book.