The Open Access Scholarly Publishers' Association's "Why CC-BY page" http://oaspa.org/why-cc-by/ refers to an "emerging consensus on the adoption of CC-BY". My comment:
Re: CC-BY - emerging consensus. OASPA refers to an "emerging consensus" that CC-BY is the best license for open access. I argue that the evidence suggests that CC-BY is a peripheral phenomenon and very far from consensus.
From Peter Suber's SPARC Open Access Newsletter, June 2012 - in brief only 11% of the journals listed in DOAJ use CC-BY, and outside of full gold OA publishing as illustrated by the journals in DOAJ, the proportion of OA that is CC-BY is lower still.
"Libre OA through repositories has been rare because most repositories are not in a position to demand it or even to authorize it. Hence, you might think that libre OA through journals would be common because all journals are in a position to do both. But unfortunately that would be wrong. The power of journals to demand and authorize libre OA means that libre gold could be common, and should be common. But scandalously, it doesn't mean that libre gold is already common...Only 917 journals in the DOAJ have the SPARC Europe Seal of Approval, which requires CC-BY. That's only 11.8% of the full set".
Suber, Peter. SPARC Open Access Newsletter, June 2012 http://www.earlham.edu/~peters/fos/newsletter/06-02-12.htm#libre