Maybe the “breakthrough” is the change in acknowledged links between people.

For example, every person immediately grasps the concept of a Facebook friend. (Or at least think they do.)

But Twitter has popularised the totally different concept of the asymmetric follow (from Flickr and others). You could argue that we’ve seen it before with RSS subscription, which is asymmetric. But the important difference is the openness of the lists. On Twitter, you know who is following you.

Actually everyone can see who everyone is following and being followed by, even for private accounts.

There is turbulence when someone is unfollowed because they often can’t distinguish it from defriending. It could be that of course. But it could just be people managing their information intake.

People use Twitter in different ways. I think of myself as a “subscriber” to the people I follow. In that sense it’s a commitment-free relationship!

A side point here is the role of ego in contributing to the growth of an online social network. “Follower” appeals to the ego. Same is true on Facebook, Myspace and so on, where “friend” is the wrong word. “Contact” would be much more appropriate. Along with the follower and friend numbers, these things are designed to appeal to schoolyard insecurities in all of us…

Joel Drapper also received a lot of attention for unfollowing thousands. (He since deleted his blog.)

People will be unhappy (and some deeply dissatisfied) with your actions if you unfollow them. But they’ll also be unhappy if you used to hang with them every week at the local McDonalds and one day you decided you had enough of McDonalds and preferred Burger King.