Relationship Symmetry in Social Networks

Interesting analysis by Joshua Porter of the difference between Twitter and FaceBook.

In general, there are two ways to model human relationships in software. An “asymmetric” model is how Twitter currently works. You can “follow” someone else without them following you back. It’s a one-way relationship that may or may not be mutual.

Relationship Symmetry in the Facebook model

Facebook, on the other hand, has always used a “symmetric” model, where each time you add someone as a friend they have to add you as a friend as well. This is a two-way relationship, and it is required to have any relationship at all. So as a Facebook user there is always a 1-1 relationship among your friends. Everyone who you have claimed as a friend has also claimed you as a friend.

The post goes on to cite Andrew Chen’s point that Twitter allows 4 types of relationships, while Facebook only allows for two. The two relationships of Facebook are “friend and Not Friend”. The four relationships of Twitter are:

1. People who follow you, but you don’t follow back
2. People who don’t follow you, but you follow them
3. You both follow each other (Friends!)
4. Neither of you follow each other

As Andrew points out, an asymmetric model allows for more types of relationships. I think the benefits go further than that. I think that the asymmetric model better mimics how real attention works…and how it has always worked.