Friends Communicate in Underlying Social Networks

by Luke Wroblewski September 8, 2009

Though online social networks are quickly growing extremely large (Facebook has over 250 million users worldwide), their mechanisms for establishing person to person relationships remain quite basic.

In symmetrical networks like Facebook and LinkedIn, a 2-way handshake is required to confirm a relationship. That is, both sides have to agree to be connected. In asymmetrical networks like Twitter, a 1-way connection is all that is required to follow someone's activities.

Despite the clear difference between these social models, I found it interesting that in both cases, messaging activity reveals a "hidden" but perhaps more connected social network.

In Social networks that matter: Twitter under the microscope, the authors found that even Twitter users with a large network of asymmetrical connections have a much smaller network of friends that is revealed by messaging activity. This "hidden" network has 90% reciprocity (mutual friendships) and drives more usage.

While the number of posts as a function of followers initially increases, it eventually saturates. So more followers encourage more contribution up to a point. However, the number of posts as a function of friends (as defined by messaging activity) continues to increase without a clear saturation point. The authors use this evidence to point out "the number of friends (not followers) is the actual driver of Twitter users' activity."

A study of messaging within Facebook's symmetrical connection model revealed a similar hidden network. Of the 378 million friend links studied, only 57 million (15%) of those friend pairs exchanged messages. Though a lack of messaging does not imply no connection, the presence of message does "constitute positive evidence of the existence of a bond." In other words, messaging activity provides a clearer signal of a personal relationship than a 2-way connection as connections can be established for any number of reasons, and "not always for reasons that imply the pair are friends in the conventional sense."

As further evidence that messaging activity can reveal meaningful relationships, researchers were able to infer from mobile data (calling records & location) with 95% accuracy if any given pair of users were friends. "The researchers then compared the data with results from standard surveys given to the mobile users - and found, as the social sciences have found time and again, that people reported different behaviour than the mobile data revealed."

So looking at actual messaging reveals a different social network than most people would "report" using either symmetrical or asymmetrical connection models.