It kinda makes sense that you can know roughly 700 people.

In planning my new course I read through Daniel Bell’s 1973 book, The Coming of Post-Industrial Society. It doesn’t really have anything so relevant for the class, so it turns out I won’t be assigning any readings from it. But I did come across one fun bit, in a footnote on page 467 which pointed to this quote from an article from 1967 by economist Martin Shubik: Each person should have 700 friends! That reminded me of something from our 2006 paper on social networks: We estimated the average person to know about 700 people. Too bad we weren’t aware of that Shubik paper or we could’ve cited it. According to wikipedia, Shubik didn’t retire until 2007 so if we’d only known we could’ve told him about our finding. Nowadays, of course, we can know lots more than 700 people, because you can know people online without ever meeting them at all!