Rufus Pollock has a new post arguing that the Share-Alike clause of the Creative Commons license is open, but the non-commercial clause is not. From the post:
To reiterate: it is a mistake to view the set of licenses as some continuous spectrum of ‘openness’ with PD at one end and full rights reserved at the other — with the implication that all licenses in between are more or less open.
David Wiley responds. Steve O’Connor on why he choses CC BY.

Thanks for any ebook at fair price of $ 5 per year.
It should not be free.
Writer has a right to get some earnings
plus it is required for sustainability.
Thanks billion for any effort for ebooks.