Does Twitter have a really low Dunbar Number?

Is Twitter really a 21st Century hive-mind network, or just the same old daisy chain? Via firstmonday, some Hewlett Packard researchers find that tweeters may be densely packed, but they ain't no flock.



[Bolding is mine]

Figures 4 and 5 show that even though the number of friends initially increases as the number of followees increases, after a while the number of friends saturates. This trend can be explained by the fact that the cost of declaring a new followee is very low compared to the cost of maintaining friends (i.e., exchanging directed messages with other users). Hence, the number of people a user actually communicates with eventually stops increasing while the number of followees can continue to grow indefinitely.

[snipped some good detail]

Many people, including scholars, advertisers and political activists, see online social networks as an opportunity to study the propagation of ideas, the formation of social bonds and viral marketing, among others. This view should be tempered by our findings that a link between any two people does not necessarily imply an interaction between them. As we showed in the case of Twitter, most of the links declared within Twitter were meaningless from an interaction point of view. Thus the need to find the hidden social network; the one that matters when trying to rely on word of mouth to spread an idea, a belief, or a trend.

Well, that potentially knocks the wheels from under certain Web 2.0 assumptions, doesn't it? But is it surprising, really? "Maintaining" friendships is high cost, always has been once we blew past the boundaries of village and clan. In those times, maintenance opportunities were likely achieved for us as the automatic by-product of constant proximity. (James Burke, The Day the Universe Changed: "Before 1450, life was intensely local. Most people lived and died in the same cottage, and never went further afield than 7 miles.")

Of course, that same syndrome, everyone knowing your every move and action, is one of the reasons the town of my wife's grandparents, Gettysburg SD, has no young people anymore.

I'd be interested in seeing how this plays out with professional (intra-)nets, like those in the previous post that Cisco is trying to plus and push. Somehow, I'd bet the binder of a paycheck and actual peers depending on you, not to mention promotion requirements, would encourage more committed flocking. Let's hope so.

Speaking of claustrophobic village-life, I wondered what wiki said about Dunbar and his number. It's funny to think of the Chamber of Commerce or First Fridays as "social grooming"...

Dunbar's surveys of village and tribe sizes also appeared to approximate this predicted value, including 150 as the estimated size of a neolithic farming village; 150 as the splitting point of Hutterite settlements; 200 as the upper bound on the number of academics in a discipline's sub-specialization; 150 as the basic unit size of professional armies in Roman antiquity and in modern times since the 16th century; and notions of appropriate company size.

Dunbar has argued that 150 would be the mean group size only for communities with a very high incentive to remain together. For a group of this size to remain cohesive, Dunbar speculated that as much as 42% of the group's time would have to be devoted to social grooming.