In April we belatedly blogged license adoption estimates for December 2005, which had been published elsewhere in December. That estimate, based on Google queries restricted to CC-licensed content, came to 45 million web pages under a Creative Commons license.

What a difference six months make. Our current aggregate estimate, also based on Google queries for CC content, comes to 140 million pages. Impressive, though it must be noted that this much higher number is probably the result of both increasing use of CC licenses and overall growth of Google’s index.

In April we also gave a current breakdown of license use by license property. Here is an updated breakdown:

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

The increased use of more liberal licenses noted in April seems to have
accelerated, though again it must be noted that some of the change may
be due to search index variability (Yahoo!’s in this case, as Yahoo!
facilitates searching for specific license URLs with link: queries).

Look for another update in December, hopefully with some indications of
adoption across jurisdictions and languages (again with many caveats).