Thanks to Matt Bogard for his work and his reference to Drew Conway’s work (2009).
Using Twitter to Demonstrate Basic Concepts from Network Analysis

*Matt Bogard*, /Western Kentucky University/

Abstract

Social network analysis focuses on finding patterns in interactions between people or entities. These patterns may be described in the form of a network. Network analysis in general has many applications including models of student integration and persistence, business to business supply chains, terrorist cells, or analysis of social media such as Facebook and Twitter. This presentation provides a reference for basic concepts from social network analysis with examples using tweets from Twitter.
http://works.bepress.com/matt_bogard/9/

Of particular importance here (and Matt draws it out in his work above) is Drew Conway’s use of SNA measures to identify key actors within a network. First, is the term “critical gatekeeper” that Conway characterizes as having a high betweeness centrality measure and a low Eigenvector centrality measure. According to Conway, these individuals connect people that would otherwise be isolated from the core of the network. Those individuals with low betweeness centrality measures and high Eigenvector centrality measures are people that are at the ‘heart’ of the core. In other words, they are individuals that are extremely well connected.
http://www.drewconway.com/zia/?p=1221