In the recent post called Twitter List Profile Clouds I explored how the Twitter list names to which a person has been added can reveal how they are perceived across the twittersphere. Another interesting idea is that when somebody adds an account to a list they are implicitly defining a relation between that account and every other account on the same list. They are essentially making a declaration that all the members of the list share some characteristic. The name of the list usually offers a clue about how all the list members are related.
So, for example, the fact that datavis and flowingdata both appear on a list together means that somebody thinks they are similar in some sense. And if the list name is called 'datavisualization' then that reveals how the list creator thinks they are similar.
I think of two accounts that appear on a list together as 'listmates'. It seems a reasonable name for the concept and follows the pattern of schoolmates, roommates, teammates etc. If you take all the Twitter Lists that an account is listed on and find all the members of those lists you can define a set of users related to the starting account. Keep track of how many times they appear in total and you also get a numeric score for how similar they are.
I tried out the idea using my own account, JeffClark, as a starting point. Here are my top 25 Twitter Listmates:
The list is a who's who of people I respect and admire in the field of data visualization and I'm very pleased that others have grouped us together. I believe this technique has promise for finding interesting new accounts to follow.