Want to know who matters to someone? 

It's usually not the biggest tweeps someone follows -- heck almost everyone follows  @BarackObama, @PerezHilton and @Mashable. 

It's the smallest, the tweeps with just 36 or 281 followers.  

In the "under the radar" list, you more likely find a tweeter's  lawyer, sister, high school BFF, 40-something-mentor-just-getting-on-twitter, and/or cubicle-mate.

Mapping those people often yields the most meaningful insights into a tweeter's social graph.