This is a really neat tool:
Old news, but new to me!
“Linked Jazz’s new visualization tool developed by Matt Miller visualizes the social connections between jazz musicians. Various modes allow the user to view the network in new ways. Fixed mode pins the individuals with the most connections to the outer perimeter. Free mode groups individuals together based on the number of connections they have. Similar mode arranges individuals based on their number of shared connections. Dynamic mode allows users to add individuals themselves and see their shared connections.”
(Via a presentation by Maura Marx, Secretariat Director, Digital Public Library of America, at the Discovery Summit 2013)