Stack Overflow is part of the Stack Exchange Network, and article 3 of the Terms of Service tell us that “You agree that all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution - Share Alike license.” (https://stackexchange.com/legal)
The Stack Exchange Network Terms of Service, give us the following advice:
In the event that You post or otherwise use Subscriber Content outside of the Network or Services, with the exception of content entirely created by You, You agree that You will follow the attribution rules of the Creative Commons Attribution Share Alike license as follows:
- You will ensure that any such use of Subscriber Content visually displays or otherwise indicates the source of the Subscriber Content as coming from the Stack Exchange Network. This requirement is satisfied with a discreet text blurb, or some other unobtrusive but clear visual indication.
- You will ensure that any such Internet use of Subscriber Content includes a hyperlink directly to the original question on the source site on the Network (e.g., https://stackoverflow.com/questions/12345)
- You will ensure that any such use of Subscriber Content visually display or otherwise clearly indicate the author names for every question and answer so used.
While this license works well for some communities on StackExchange –for instance, it works well if you want to share a recipe for Eggs Benedict found on cooking.stackexchange.com–, it doesn’t work well for source code.
The Creative Commons FAQ recommends against using Creative Commons licenses for software. Instead, they strongly encourage to use one of the very good free / open source software licenses which were already available. See https://creativecommons.org/faq/#can-i-apply-a-creative-commons-license-to-software
The Creative Commons FAQ also explains that:
Unlike software-specific licenses, CC licenses do not contain specific terms about the distribution of source code, which is often important to ensuring the free reuse and modifiability of software. Many software licenses also address patent rights, which are important to software but may not be applicable to other copyrightable works. Additionally, our licenses are currently not compatible with the major software licenses, so it would be difficult to integrate CC-licensed work with other free software.
In my quest for more information about this topic, I stumbled upon this link: The MIT License – Clarity on Using Code on Stack Overflow and Stack Exchange where I read:
Starting Feb 1, 2016, all new code contributions to Stack Overflow and Stack Exchange will be covered by the MIT License.
As far as I understand the change would make it easy for developers providing answers containing source code on Stack Overflow, in the sense that:
- Non-code contributions will continue to be available for use under the terms of the CC-BY-SA,
- Code contributions will be available for use under the terms of the MIT License,
- You don’t have to include the full MIT License in your code base.
Additionally, the Stack Exchange Network proposed a notice preservation exception, stating that developers who use code found on Stack Overflow, don’t have to include the full MIT License in their code either. They can choose between these two options:
- Add a comment to your code that links back to the post where you found the code, or
- Comply with the MIT as it’s typically used, by including the full license text in your source.
In other words: if you don’t want to add the MIT License to your code base, it is sufficient to add a link to Stack Overflow. If you want to make sure that the code you're using if 100% compatible with your own license, you can add the MIT License.
This post dates from December 2015 and was last edited in January 2016. The post ends with the following remark:
We hope to roll this out February 1, 2016. We know it’s short notice, but we think the proposed terms are a decisive improvement over status quo, and so a change probably can’t come early enough. Please let us know what you think.
My question is: Was this operation successful? Did the Stack Exchange Network succeed in making this change to the Terms of Service?
Maybe I overlooked, but I don't see any changes to the Terms of Service that mention the MIT License for source code. The most recent question on "Open Source beta" still talks about the CC-BY-SA only: Must CC BY-SA be included for ideas and code taken from Stack Overflow?
Could anyone point me to an official page that informs me:
- If source code shared on Stack Overflow can be used under the MIT License,
- If the proposal to make source code on Stack Overflow available under the MIT License was rejected.