Yesterday Yahoo! announced that their search index had grown to 20 billion documents. That, along with continued adoption of Creative Commons licenses, explains 53 million linkbacks to our licenses according to Yahoo! linkback queries. In May, when Yahoo!’s index apparently consisted of 8 billion documents, we found 16 million pages with license links. So discounting the growth of Yahoo!’s index, the number of Creative Commons license links have increased by approximately one third in the past three months alone — 53/(16*(20/8)) = 1.325. Take the exact numbers with a lump of salt, but the indication of growth is impressive nonetheless.
You can search for Creative Commons licensed content at Yahoo! Search for Creative Commons.