Who have I been talking to?

One of the most frequently used ways to communicate with others is email. We have created "Who Have I Been Talking To?", a visualization of the users' email that can provide insights about their relationships with others how one relation has evolved over time (reflected by the number of messages exchanged); the nature of the relationship (comparing the subjects of messages and how asymmetric is the ratio between sent and received email); and allowing users to compare their relationships with different people. We found that a variant of a stacked bar chart over an interactive timeline allowed all of those goals to be achieved. User studies showed that the users were able to understand the visualization and gain meaningful insights about their electronic communications with others.