タレコミした者です。 おそらくはCCとGPL（あるいはFDL）が相対する関係にあるとの認識から「競合」と指摘されたのだと思います。しかし引用元http://creativecommons.org/weblog/entry/7252 [creativecommons.org]を見ていただければ分かりますが BY-SA － Compatibility Structure Now Included The CC BY-SA 3.0 licenses will now include the ability for derivatives to be relicensed under a “Creative Commons Compatible License,” which will be listed here. This structure realizes CC’s long-held objective of ensuring that there are no legal barriers to people being able to remix creativity in the way that flexible licenses are intended to enable. More information about this is provided here. CCとCompatibleなライセンスをCCで決めて、CCのby-saと同様にShareAlike（「継承」）な性質を持ったライセンスと互換性を持たせる予定となっています。脚注http://wiki.creativecommons.org/Version_3#BY-SA_.E2.80.94_Compatibilit... [creativecommons.org]によればLessig先生もこう言っています。 "Even if all the creative work you want to remix is licensed under a copyleft license, because those licenses are different licenses, you can’t take creative work from one, and remix it in another. Wikipedia, for example, is licensed under the FDL. It requires derivatives be licensed under the FDL only. And the same is true of the Creative Commons Attribution-ShareAlike license that governs Opsound content, as well as much of the creativity within Flickr. All of these licenses were written without regard to the fundamental value of every significant advance in the digital age — interoperability." 要約すると理念を同じくするライセンス同士で大同団結しようというということでしょうか。 以上のような文脈を踏まえたうえで「協合」としました。