An interesting study by Bernardo A. Huberman, Daniel M. Romero and Fang Wu over at HP on the social interactions within Twitter. To quote from the preamble:

Scholars, advertisers and political activists see massive online social networks as a representation of social interactions that can be used to study the propagation of ideas, social bond dynamics and viral marketing, among others. But the linked structures of social networks do not reveal actual interactions among people. Scarcity of attention and the daily rhythms of life and work makes people default to interacting with those few that matter and that reciprocate their attention. A study of social interactions within Twitter reveals that the driver of usage is a sparse and hidden network of connections underlying the “declared” set of friends and followers.

Key points from the report:

1. A ‘friend’ is loosley defined as anyone the user has directed at least two posts (tweets) to.
2. They conjecture that users who receive attention from many people will post more often than users who receive little attention.
3. Users with more followers and friends will be more active than those with a small number of followers and friends.
4. There are two different networks: a dense one made up followers and followees, and a sparser and simpler network of friends.
5. The number of friends is the actual driver of the user’s activity and not the number of followers.
6. Users with many followers post updates less frequently than those with few followers.

The full report is available at the HP website link above, or can be downloaded here.