Hugh Pickens writes "Back in early '90s, British anthropologist Robin Dunbar began studying human social groups, measuring the number of people an individual can maintain regular contact with, and came up with 150 — a number that appears to be constant throughout human history — from the size of neolithic villages to military units to 20th century contact books. But in the last decade, social networking technology has had a profound influence on the way people connect, vastly increasing the ease with which we can communicate with and follow others, so it's not uncommon for tweeters to follow and be followed by thousands of others. Now Bruno Goncalves has studied the network of links created by three million Twitter users over four years. After counting tweets that are mutual and regular as signifying a significant social bond, he found that when people start tweeting, their number of friends increases to a saturation point until they become overwhelmed. Beyond that saturation point, the conversations with less important contacts start to become less frequent and the tweeters begin to concentrate on the people they have the strongest links with. So what is the saturation point? The answer is between 100 and 200, just as Dunbar predicts. 'This finding suggests that even though modern social networks help us to log all the people with whom we meet and interact,' says Goncalves, 'they are unable to overcome the biological and physical constraints that limit stable social relations (PDF).'"