Dotful Data Visualization by Stamen
Cheerio Maps is a view of housing data from http://www.ziprealty.com/ that Stamen visualized in early 2010. The maps look at how the sizes, prices and ages of houses vary across the San Francisco Bay Area, and uses circles of different sizes to denote greater and lesser values. In the first image below: Housing prices in San Francisco. Each dot is a house for sale, and the big green dot behind everything else is a mega-mansion in the Pacific Heights neighborhood.