Let's say that I make a post on a Stack Exchange site. That content is owned by me, but I gave the company a perpetual and irrevocable license under Creative Commons Attribution Share Alike 3.0. As long as that content is available under CC-BY-SA, anyone can reuse it under those terms.

Let's say I post the exact same content on a website, but license it under "all rights reserved" or CC-BY-NC-ND. Anyone doing a Google Search will likely find the material on the Stack Exchange site where it was posted, which would include the CC-BY-SA licensing information. If that license is appropriate for their uses, then they can use it.

CC-BY-SA is pretty forgiving. The only thing that it requires is attribution to me, identification of changes, and release under the same license. That last one is, perhaps, the biggest sticking point for someone to reuse my content, since it discourages commercial use.

The only case mentioned so far is if all of the CC-BY-SA sources stopped releasing the content under that license (for example, there were no mirrors of my content and Stack Exchange shut down and did not make the content available anymore). Then, if it's only available under the more restrictive license, that's what people have to work with.

With the exception of all sources of the CC-BY-SA content stopping distribution under that license, is there any advantage to a stricter license, such as "all rights reserved" or CC BY-NC-ND?

  • I noticed a down vote without a comment. If someone has advice to improve this question, please ping me. I think the question fits the scope of the site and is narrow enough to be answerable, but if I'm wrong, I'd like to refocus or clarify any issues. – Thomas Owens Nov 20 '15 at 23:38
up vote 6 down vote accepted

The simple answer is no, it doesn't make much sense.

You've posted this work on Stack Exchange, where it's licensed under CC BY-SA. I go and copy your work, use it in something I'm doing, and release it perfectly legally under BY-SA. My use case is legal, yes?

Bob sees what I've done, and sees the attribution to you. He decides he likes your work, and he wants to use it too. So he follows my link to your original, only to discover a 404 Not Found. However, he's clever enough to follow my other link to your website, where it's distributed under CC BY-NC-ND.

At this point, there are two possible ways it could go.

  1. Bob wants to make something based on your work and sell it. The BY-NC-ND license disallows this. Bob says to himself "oh well, I'll just go ahead and use it under BY-SA".

    You may not want Bob to do this, but there's no way of stopping him. Unless he was incredibly stupid about it, you can't prove that he didn't get hold of your content back when it was on Stack Exchange, and has just spent a long time making his derivative. Essentially, you can't prove you didn't license it to him under BY-SA. This is a slightly iffy use case, and not entirely legally sound (though it's pretty good), but he would likely get away with it. However, if he wants to stay entirely legally correct, there's an even easier way.

  2. Bob got to your work through my work. My work was created and released when the content was on Stack Exchange. You licensed that to me under BY-SA for sure, so there's no doubt my use is legal. When the license on your work changed because Stack stopped distributing it, that didn't make my work illegal because I've already got the license.

    Bob can simply use my work. I have the right to distribute that under BY-SA, and to grant him the right to do so via the license. Hence, he can make his derivative a derivative of your work in my work, if that makes sense. He attributes back to me, which attributes back to you. The license conditions are satisfied, and the lawyers can't complain.

You can dual-license under a more restrictive license if you want to - some people won't know that it was originally licensed under BY-SA, and will use it under BY-NC-ND - but just bear in mind that once licensed, always licensed.

There is not really much of a point licensing your content strictly more strict than the one you already licensed it under. For example, there is nothing you are allowed to do with CC BY-NC-ND that you're not also allowed to do with CC BY-SA. As you said, they can always pick up a copy from the alternative source under the different license.

There can be reasons to still do this. For example, if you have a blog, and you have a standard (more strict) license that applies to it, it would be convenient not to change that for a single piece that's available elsewhere as CC BY-SA. This is purely an argument of convenience, the content will still also be available under CC BY-SA when they receive it from a StackExchange site.

Some licenses are not strictly more strict, but have different restrictions. For example, you could license your content with a non-transferable license without the SA requirement for pay. Of you could additionally license your content under a hypothetical license that doesn't require attribution, but doesn't allow commercial use.

In those cases it can also make sense to dual-license.

  • 1
    Would you say that it depends on the rest of the content, assuming that not all of the content is available somewhere else CC-BY-SA? That would be the driving factor? It's easier to apply a strict license to all blog content and then identify things that are CC-BY-SA (or another open license). The license on a blog should identify how you want people to generally use the content posted there, and then identify if a particular post is also available under a more open license? – Thomas Owens Nov 21 '15 at 20:07

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