It's great that the author decided to do this work. TL;DR: The Dunbar numbers are significant for online social networks too. People working in TCS on "social

It's great that the author decided to do this work. TL;DR: The Dunbar numbers are significant for online social networks too. People working in TCS on "social networks" often work with TCS tools, which are inherently asymptotic. Thus they conclude some stuff on social networks, while assuming that the number of "friends" per person tends to infinity, without seeing much of a problem concluding that it's what happens in "the real world". To be fair, one excuse is that more realistic models are often not mathematically tractable (yet), but it doesn't excuse making wild conclusions.