Extracted 20OCT2011 from http://mashable.com/2011/10/19/google-analytics-launches-in-depth-flow-visual...
Flow Visualizations is a dynamic way to view and experience your Google Analytics data. It utilizes the lens of a Sankey diagram, a specific type of flow diagram. Flow Visualizations allow sites to drill into user behavior based on location, browser, user type and many other variables.The key to Flow Visualizations, though, is its ability to analyze how visitors are using a website. These visualizations allow website administrators to figure out where people are visiting, how many people stay on their site, how many people visit a site’s shopping cart and more. Wojcicki said the inspiration for the new product actually came from a Sankey diagram from the 19th century, describing the marching movements of Napoleon and his army over the course of time.
See more on Sankey Diagrams:
Google Analytics at http://analytics.blogspot.com/2011/10/introducing-flow-visualization.html
Wikipedia at http://en.wikipedia.org/wiki/Sankey_diagram
Images at http://tinyurl.com/3hc85fj