Thread Arcs
When a message is selected a thread map appears providing a visualization of the message's response hierarchy. The currently selected message, along with arcs to its parent and children, are highlighted with blue. Unread messages are indicated with a black border. Messages that the user has sent are hollow. Our design maintains compactness with either deep or wide trees, while clearly displaying chronological order (older messages are drawn to the left). A full description of Thread Arcs design is described in detail in the THREAD ARCS: An Email Thread Visualization publication.