Not sure this accounts for the fact that social networks, unlike galaxies or the universe can be folded and reconstituted at will. If you think of it like making a pizza, you spin the dough and as it spins it will eventually break apart (mySpace, Tumblr, your-favorite-forum-of-yore) but you can always fold it back over itself. In this metaphor, Facebook's introduction of new features and its acquisition of Instagram, WhatsApp and forthcoming VR (in a way its own universe, without any natural law like entropy) represent folding - reconstitutions and renewals. I suppose we can conclude that if entropy represents a fundamental part of natural law applicable to social networks, our technology will try to negate and dominate it. At the very least and assuming the thesis of the paper to hold true we can say, Social Networks are doing something about it.