I'm a great admirer of Creative Commons. But the simple truth is that CC is
second class. Both under law and in fact.
Copyright exists under federal statute. CC doesn't have a similar status.
The creator of a work has automatic
legal copyright under US law. The creator may choose
not to assert his/her rights under copyright law. And he/she may also
choose to license
(which is not the same thing as copyright) their work under whatever model they wish. But simply putting a work under CC does not make the copyright legally "go away" or otherwise invalidate it.
A creator of a work holds copyright on their original works whether they want it or not
. The courts have been very clear on that point. Interestingly, that issue first came up when somebody (who was allegedly in violation of a CC license) argued in court that putting a work under CC waived the author's right to copyright - and then went on to also argue that CC was not legally binding.
The court said (and it's since been affirmed in several other cases) that CC is legally binding and enforceable under contract law. And even if it weren't, the author still held legal copyright
for the work under US statute regardless
of any supplemental assignment or licensing arrangement they elected to release the work under. And furthermore, copyright was not something the author could legally waive even if they wanted to do so.
You create something - you've got copyright under federal law. Period. If you want to also put it under CC, that's your business.
Even putting something into public domain is really just irrevocably assigning
the copyright to the general public for free use. It doesn't invalidate or negate the original copyright itself. The copyright only goes away when it expires under statute - which (in the USA) is generally the lifetime of the creator plus 70 years. Or when something gets put into public domain, in which case it 'expires' immediately.