The chord diagram is a data visualization displaying the relationships between data. The data is arranged in a circle with the relationships represented as arcs between segments.  

A good example of a chord diagram is showing the states people live in now compared to where they grew up.  This diagram will show the trend in the migration of people to and from various states.

The d3 Chord Diagram add-on supports both SWF and HTML5 output from Xcelsius.