This study is about the structure embedded in e-mail relationships. Based on data describing organizational e-mail exchanges, this research deals with organizational structure, personal power, and the centrality of people in a network. Social network analysis is used to study the centralization dimension of the structure embedded in the data. The data concerns 385 employees of 36 firms within a group. Our empirical study first explores several possible assessments of power and centrality concepts; then, it tests a causal relationship between personal and organizational attributes of power and centrality indexes. Results show the relationships between personal characteristics, aspects of organizational power, and e-mail network centrality. A discussion of the way managers may use electronic communication data to better interpret the nature and the dynamic of the organizational structure concludes the article.