Development of Creative Commons licenses

[Gregory Maxwell <gmaxwell AT gmail.com>]

On Sun, Jul 22, 2012 at 9:25 PM, sebastian nielsen
<nielsen.sebastian AT gmail.com> wrote:
> The point of the SA license is to prevent a creator from releasing his
> derative works for example under public domain or under a "copyright
> reserved" non-CC license, so new creators can adapt on the derivate
> works.

All of the Creative Commons licenses you're talking about are
"copyright reserved".

The primary purpose of a copyleft license like the SA licenses is
prevent the addition of restrictions in copies or derivatives that
would encumber the further freedom of the resulting work. Almost the
entirety of the additional terms between SA and By are prohibitions
against addition restrictions on the use or redistribution of the work
or its derivatives, such terms can't be said to be upheld while also
applying restrictions. For situations where additional restrictions
are not believed to be harmful the CC-By licenses should be used.

Applying NC restrictions to a CC-By-SA work is a fine example of
additional restrictions and it's rightfully prohibited. The resulting
incompatibility is certainly unfortunate, but insoluble and I believe
the right approach is to discourage, and eventually discontinue the
ambiguous, often misunderstood, "copyright-restrictive" -NC licenses.

For more information on how the NC licenses are harmful, please see
http://freedomdefined.org/Licenses/NC