http://www.neurosciencemarketing.com/blog/articles/your-brains-twitter-limit-150-real-friends.htm
Long before Internet-based social networks existed, British anthropologist Robin Dunbar proposed that the size of our brain’s neocortex limited the number of stable social relationships a human can handle. He estimated that it was between 100 and 230, with 150 being the most commonly used single value. This has become known as “Dunbar’s Number.”
Scientists at Indiana University decided to put Dunbar’s Number to the test by analyzing the Twitter activity of 1.7 million individuals. The team, led by Bruno Goncalves, found that Twitter users’ relationships topped out in the exact range predicted by Dunbar: 100 to 200 maximum. (Full paper: Validation of Dunbar’s number in Twitter conversations.)
