So after the fun of Pandora to organize music, I thought you might like this example:
Pretty picture you say? Well, how about a couple of thousand. The wheel represents the colors used in Flikr photos over a one year span:
More pictures of white snow in the winter and green grass in the summer. Check out http://hint.fm/projects/flickr/ for more information.
One last little thought…this is an example of how humans (in this case a designer) organizes a huge collection of information, not just some blind algorithm. I love how information organization is seen here as much about art as informing.