Collaborative data and graphing site Swivel (blogged here — copyrightable elements are under CC Attribution) now features a dataset mapping the growth of CC licensing at Flickr over the last eleven months:
Challenge: add datasets for other CC enabled content repositories to Swivel.
Beth Kanter remixes.
Jared Benedict writes about gathering the data and also making it available in tab delimited format and as a Google spreadsheet.
Another challenge: Gather older data points from http://web.archive.org/web/*/http://flickr.com/creativecommons. In October 2004 there were fewer than 100,000 CC licensed images on Flickr.