Brianna Laugher wrote: [...]
After rereading the CC-BY legal code it does appear you (and others who made this point) are correct, and I was quite mistaken about the strength of the CC-BY license. http://creativecommons.org/licenses/by/3.0/legalcode "You may Distribute or Publicly Perform the Work only under the terms of this License."
Indeed it seems CC-BY is already the "weak copyleft" I was thinking CC-BY-SA is... CC-BY is much stronger than I realised. I thought CC-BY just meant "include a byline with my name".
No it isn't, there is one important difference: derivative work, i.e. modified versions. Again, compare to the LGPL: modified versions must be distributed under the same license (though larger works which use/incorporate clearly demarked LGPL components do not). This is not true for CC-BY: if i make a derivative of a CC-BY work, I have to attribute the author, but i can license my version under whatever conditions i like. That's not weak copyleft, that's no copyleft at all.
So, is this understanding correct: using CC-BY, a reuser could create a derivative work that was not freely licensed, but provide info that the source image was CC-BY (and provide link), and that would be acceptable? Is that true?
Yes, that is correct, but again, we lose the distinction of using/aggregating works, and modifying them. I believe this is a very important difference (as exemplified by the LGPL), and I maintain that an LGPL-Like CC license would be useful - at least for me, it would reflect exactly what I, for one, want:
People can *use* my work *in* theirs, as long as they attribute me, but if they *modify* my work, that modification must be freely licensed. This is stronger than CC-BY but weaker (or rather, softer) than CC-BY-SA/GFDL (in their "strong" interpretation).
Well... now I think shoring up CC-BY-SA to be a strong copyleft is a good idea, since Greg is correct...if we can correct the misperceptions of people like me then I don't see why this idea wouldn't receive widespread support.
I think having a clearly strong/viral CC-BY-SA is just as important as having a soft version. Of course, adding yet another license to the mix is not so great, but I would hope that having *clearer* labels will clear up more confusion than adding *another* label creates....
-- Daniel