Jyri Engeström recently wrote a thoughtful post on the reasons why some social network services succeed, and others do not. Engeström’s hypothesis, which he labels “object centred sociality”, follows the thinking of sociologist Karin Knorr Cetina. Basically, “object centred sociality” takes the stance that it makes little sense to discuss ‘social networking’ if we ignore the “objects that mediate ties” between people. “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.”

Engeström cites success stories such as Flickr (object = photograph) and del.icio.us (object = URL), and alternately, less successful services (e.g., LinkedIn) where the object is not as explicit, or even absent.

It’s an interesting argument backed by some really compelling sociological theory. I recommend taking a look.