Facebook Relationship Management: does it increase personal network size?

Facebook Data Team did some research on relationship management through Facebook, which was used in the article “Primates on Facebook” in the Economist.
The question being: is Facebook increasing the size of people’s personal networks?
Social networks provide a means of relationship management through passive engagement, a one-way communication of observing activity in their network. Facebook provides the News Feed as a way to monitor your network’s activity.

Here we can see that there is a one-way communication with half our total network.