Here's a brief case study of how one book under a Creative Commons license evolved and was accessed.
In 2005, the Association of Research Libraries published my book, the Open Access Bibliography: Liberating Scholarly Literature with E-Prints and Open Access Journals, under a Creative Commons Attribution-NonCommercial License. With ARL's agreement, I made an open access PDF available on Digital Scholarship.
In 2010, I published Transforming Scholarly Publishing through Open Access: A Bibliography as an open access PDF file, an open access XHTML website, and a low-cost paperback. All versions of the bibliography were under a Creative Commons Attribution-Noncommercial License. This derivative work was an updated version of the Open Access Bibliography that was more narrowly focused on scholarly treatments of open access.
Below are the Digital Scholarship use statistics for the two books as of October 31, 2014. In this analysis, only HTML files or PDF files are counted as "page views"; image files and other supporting website files are excluded. This analysis also excludes spider use.
- Open Access Bibliography: Liberating Scholarly Literature with E-Prints and Open Access Journals: over 355,000 page views.
- Transforming Scholarly Publishing through Open Access: A Bibliography: over 152,000 page views.
That's a total of over 507,000 page views. For the measured time period, about 7.9% of all file requests to Digital Scholarship failed. Consequently, I'll eliminate 7.9% of the above page views and estimate that there were over 466,000 successful page views. This tally does not include any access statistics from ARL or the OAD (nor does it include paperback sales).
If the multi-file HTML versions of the books are eliminated from consideration, the two books still had a total of over 173,000 PDF requests (excluding spider requests), adjusted to an estimated 159,000 plus successful PDF requests.
To put these use statistics in perspective, in 2005, Willis Regier (Director of the University of Illinois Press) estimated that the typical university press book sold between 400 to 800 copies.