It’s been awhile since the last time we posted estimates of the number of web pages under a Creative Commons license or a breakdown of how those licenses are distributed. The last aggregate estimate (45 million) was posted to our support the commons page in December, which has since changed (thanks yet again for your support!). The estimate appears in at least two interviews of our chair published on the web December and January at Technology Review and The Guardian.

We frequently get asked about license adoption, so I’ve created a page on license statistics that you can always visit for current and links to historical estimates and other statistics. Expect an updatedaggregate estimate every six months — next in June.

In addition to coarse estimates based on search engine queries we also have some promising growth numbers from individual CC-enabled content communities and curators. As of early this month Flickr hosted 10.8 million CC-licensed images and Soundclick hosted 219,000 CC-licensed songs, up from 4.1 million and 159,000 in August. Revver hosts 20,000 CC-licensed videos and did not launch until November. These are only a few of many CC-enabled hosts.

There have been some small changes in the types of licenses being used since last February. A current chart is reproduced below, see the previous link for a year-ago chart.

Distribution of licenses deployed. Those without ‘by’ (attribution) were not versioned past 1.0 (excepting public domain, which is not versioned).

The small change appears to be in the direction of using more liberal licenses. Attribution, Attribution-NonCommercial and Attribution-ShareAlike all gained bigger slices of a (much larger) pie while Attribution-NonCommercial-NoDerivs, Attribution-NonCommercial-ShareAlike and Attribution-NoDerivs have smaller shares relative to a year ago.

The proportionate use of the NonCommercial, NoDerivs, and ShareAlike properties have all declined slightly due to the increased use of more liberal licenses (with fewer prohibitions and requirements).