Google+ Ripples [plus.google.com] is the first data visualization project from the elusive Big Picture Group, organized around (previous IBM Visual Communication Lab pioneers) Fernanda Viegas and Martin Wattenberg. It is a working demonstration how aesthetics and functionality can still be effectively be merged.
The 'Ripple Diagram' shows how a post spreads as people (publicly) share it using the Google+ service, with arrows indicating the direction of the sharing. A timeline at the bottom of the diagram allow the ripple to animate, revealing how this post was shared over time. People who have reshared the post are displayed with their own circle. Inside the circle are people who have reshared the post from that person (and so on). All circles are roughly sized based on the relative influence of that person.
The diagram can be created based on any public post in one's stream, by clicking the dropdown arrow at the top of the post and selecting "View Ripple". Using the metaphor of ripples that propagate and alter the state of their environment, the tool seems particularly useful for marketeers, viral social media managers and the like, as they now can include the intriguing graphics in their social impact and SEO reports.
More detailed information about G+ Ripples available here.