Research from the Harvard Business school has found that “the top 10% of prolific Twitter users accounted for over 90% of tweets. On a typical online social network, the top 10% of users account for 30% of all production. To put Twitter in perspective, consider an unlikely analogue – Wikipedia. There, the top 15% of the most prolific editors account for 90% of Wikipedia’s edits. In other words, the pattern of contributions on Twitter is more concentrated among the few top users than is the case on Wikipedia, even though Wikipedia is clearly not a communications tool. This implies that Twitter’s resembles more of a one-way, one-to-many publishing service more than a two-way, peer-to-peer communication network.”
I would like to see research that shows the relative utility of Twitter vs. social networks as the size of your followers/followed network increases. My thesis is that the bigger your Twittersphere, the less utility it has — the reverse I would think would be true of social networks.