I could've sworn I had posted about this before but I can't find it..but talk about old...the spur for this post is from 2005!
Now I saw this post in the Adaptive Path blog like a week or two ago; "The Shelf Life of Social Networks." The post seems to be asking about why there seems to be a rise and fall to social networks and should we worry about that or just go along with it. While at the Adaptive Path conference, UX Week 2007, I had seen this session and thought it was quite good; "UX Design as Communities of Practice." This of course led me back to re-read Etienne Wenger and then for some disjointed reason, I thought of this post from 2005.
The author, a PhD student named Jyri Engestrom, is interested "in the relationship between technical innovation and organizational transformation." The post in question is titled "Why some social network services work and others don't — Or: the case for object-centered sociality" and focuses on changing the discussion of why social networks seem to fade in and fade out of consciousness and usefulness not by looking at the network per se but seeking to understand why the network exists in the first place. Engestrom argues that any comparison of social networks without considering the underlying "object" at the heart of the network (LinkedIn=jobs, Facebook=friends) is too rough and conflates the networks with the objects; "The fallacy is to think that social networks are just made up of people. They're not; social networks consist of people who are connected by a shared object."
So then we can ask ourselves, is it really the half-life of a network we are looking at or rather the half-life of that network's associated object. That might grant us a different perspective on how people grow into and out of certain networked experiences. Anyway, I also find it interesting that we are still having this discussion two years down the line without having seemed to advance the sophistication of our models (or my own models anyway).