In the footer of Stack Exchange sites, it is stated that user contributions are licensed under CC-BY-SA 3.0 with a contradictory and incompatible attribution requirement addendum.

The “attribution required” text links to a blog post dated 25-Jun-2009 by Jeff Atwood, which appears to be more of a personal rant than a serious license specification.

The post quotes part of an outdated human-readable summary of CC-BY-SA 3.0 that was revised on 26-Nov-2013 to better reflect the actual license wording. The post then sets out attribution requirements that are incompatible with, specifically voided by, or otherwise nulled by the Creative Commons license.

Section 3 (Subscriber Content) of the Network Terms of Service reiterates the attribution required blog post requirements as a list of 4 points:

a. 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.

b. 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)

c. 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.

d. You will ensure that any such Internet use of Subscriber Content Hyperlink each author name directly back to his or her user profile page on the source site on the Network (e.g., https://stackoverflow.com/users/12345/username), directly to the Stack Exchange domain, in standard HTML (i.e. not through a Tinyurl or other such indirect hyperlink, form of obfuscation or redirection), without any “nofollow” command or any other such means of avoiding detection by search engines, and visible even with JavaScript disabled.

This specification of linking mechanics is extraordinary and beyond the scope of the license attribution requirements.

License modifications are excluded by the CC license legal code (the license wording), and Creative Commons trademarks and logos may not be used in conjunction with any derivative or adapted license.

Jeff clearly misunderstood the license and what the former human-readable summary meant by “attribute the work in the manner specified by the author”, which is (and always has been) expressly prescribed and limited in the license terms.

Creative Commons licenses are designed to unify and simplify licensing so that people know exactly how they can use content. Inserting arbitrary additional conditions defeats the object and spirit of Creative Commons.

Such a prominent case of distorting Creative Commons licensing, by specifying exact linking mechanics, erodes the purpose of Creative Commons, and encourages others to attempt to impose their own idea of “fair” linking with animated GIF images required.

Furthermore, there are distinct classes of copyright works involved and a lack of clarity in licensing.

Copyright Works:

Individual Post - each individual question, answer or comment, licensed by the contributing users (original author and any editing users). Copyright owned by contributor(s) and clearly licensed under CC-BY-SA 3.0.

Question Thread - each single question thread, made up of a question and one or more answers and/or comments. Copyright owned by all contributors who shape the thread and possibly partly owned by Stack Exchange (to the extent that the platform facilitates the structured creation of the thread as a Collection). This is a grey area. Is a Question Thread a collective/derivative work - an evolving document, with each post/contribution deriving context from the thread - or merely a collection of separate works? If it is considered a collection, the collection itself in this case would still be subject to the CC license, as it is within the scope of “user contributions” (plural) and users definitely build the collection document by their contributions.

Collection of Questions - substantial set made up of multiple questions or question threads and associated metadata - as a whole (entire database) or subsets organized by metadata (e.g. date, tag, status). Copyright in the collection is surely owned by Stack Exchange. How is this licensed? A collection of CC licensed works is not itself subject to CC licensing. Does Stack Exchange expressly license its rights in such collections, which is outside the scope of “user contributions”? Where is this license grant?

If Stack Exchange wants to impose its own attribution requirements or use restrictions, it should do so under a separate license agreement for its intellectual property rights in Collections not covered by CC licensing.

  • 4
    I think the TOS section 2 doesn't apply to the CC-licensed parts, the TOS deal with "network content" and "subscriber content" separately. Commented Jun 5, 2015 at 8:22
  • What Mad Scientist says - that section clearly applies to (other than Content posted by Subscriber (“Subscriber Content”)). The question who owns edits and such, and who owns the data dump Metadata is interesting, and definitely worth exploring, but arguably more on the academic side of things.
    – Pekka
    Commented Jun 5, 2015 at 10:01
  • 1
    @Pëkka I think it's a bad idea to have this prominent blog post that arguably contradicts the actual licence (and had no legal meaning, as far as I understand it). The actual licence text regarding attribution looks very reasonable to me, and I think SE should replace the blog with a non-legalese version of that. Commented Jun 5, 2015 at 10:06
  • @Mad yeah, looking into it further and reading through the license, I'm starting to agree.
    – Pekka
    Commented Jun 5, 2015 at 10:07
  • 2
    Still, the bit based on the "personal use" misunderstanding should be removed from this post. It's factually incorrect and distracts from the valid points it makes.
    – Pekka
    Commented Jun 5, 2015 at 10:13
  • You're right, the “Subscriber Content” terms section reiterates the blog post; I quickly added the part about the Network ToS right before posting after seeing it referenced in another question. I should have thoroughly checked the document before mentioning it. I've updated the question to reflect that the ToS does not in fact contradict the "attribution required" blog post, as originally stated.
    – Kris
    Commented Jun 5, 2015 at 15:36
  • 3
    care to share which aspects of the licence are incomparable with, void out, or nullify the points that Jeff has listed out there? You've stated that they're incomparable, but not actually provided any evidence to support it.
    – Servy
    Commented Jun 5, 2015 at 15:49
  • 2
    I have posted a question at about this! Commented Jun 7, 2015 at 0:10
  • @curiousdannii: The question is not visible to mere mortals because law.SE is in private beta.
    – chirlu
    Commented Jun 7, 2015 at 9:11
  • @chirlu It's in public beta now! Commented Jun 8, 2015 at 21:42
  • 2
    Part of this was also discussed in SE should stop using the CC logo. +++ Related question about changing/updating the "attribution required" page: “Attribution Required” misses requirement to reference the license.
    – unor
    Commented Jun 9, 2015 at 0:39
  • 1
    It's really rather baffling to me SE has still not fixed their arguably fraudulent mislabeling of their licensing terms. Either they are using the CC or they are not; CreativeCommons is very clear on this matter, and SE is in the wrong.
    – user295616
    Commented Jun 1, 2016 at 20:05

3 Answers 3


The applicable license here is CC-BY-SA, which specifies in fairly clear terms what they mean by "attribution required". Heck, they even provide this handy table for comparing the exact attribution requirements across license version! Any reasonably-intelligent person acting in good faith need not read further; they have all the information they need to abide by the license.

So why, less than a year after Stack Overflow's launch, did Jeff feel the need to write not just one but two blog posts about this? He explains this himself, twice:

I thought it was pretty clear what “attribution” meant, but given the semi-scammy way the content is popping up in some seedier areas of the internet, maybe not


This is about the spirit of fair attribution. Attribution to the website, and more importantly, to the individuals who so generously contributed their time to create that content in the first place!


lately we’re getting a lot of reports of sites reposting our content (which is totally cool, and explicitly allowed), but not attributing it correctly … which is most decidedly not cool.


I’m always happy for our content to get remixed and reused, but at some point we have to start defending our attribution guidelines, or we are failing the community who trusted us with their content in the first place.

Defending Attribution Required, August 11th, 2010

See, every week for years now we've getting piles of emails from folks who've found their work shamelessly ripped off by some other site, with no credit given. Sometimes there'll be a halfhearted reference to Stack Overflow somewhere on the page, perhaps even with a link (carefully obscured to make it as hard as possible for anyone to associate it with the actual post)... Perhaps you could even argue that, if you squint reeaaally hard, they're abiding by the letter of the attribution requirement... But not the spirit of it.

If you're acting in good faith, then attributing the author means letting your readers know who wrote the material you're publishing. If someone visits your site and reads a post that I wrote, and walks away thinking someone else wrote it... ...then it doesn't matter how much CSS-obscured fine print you crammed in at the bottom of the page, you are violating the intent of the license.

Now, again, you'd think this would be obvious. I would. Jeff did. But people being people, there are plenty of folks more than willing to claim confusion and ignorance when confronted with their sketchy behavior. "Oh, you mean saying this was written by you and then linking your name to a page on my site is misleading? How ever could I have known that??" "Oh, you mean I shouldn't be using shady SEO tricks to try and convince Google that I'm the original source of your work? Why ever would this bother you??"

Yeah. People are scandalous. We can't change that, but we can sure as hell avoid giving them the fig-leaf excuse of "honest confusion".

I'm not a lawyer; if something like this went to court, I don't know exactly where the line would fall between "doing the bare minimum necessary" and "flagrantly violating the intent of the license". But I'd argue that if you have to ask then you're going about this all wrong: the requirements in the license aren't onerous or confusing, and if perchance you're unsure on some minor point then the ones in that blog post linked to on every page of the site should surely make things clear for you.

OTOH, if you have a problem giving credit where credit is due, then that's something of a personal issue; we've done everything possible to make it easy for you to go forward with a clear conscience; if you're uneasy about ignoring parts of it, then maybe you should ask yourself why it's so important that you do so...

  • 13
    I've no sympathy for all those scrapers at all, but that is not really the issue here. The CC license is a good choice, it's a really strong argument for SE in my opinion, but that's not what this is about at all. The TOS and Jeff's blog post are not about the CC license, but a variation of it, and that's the confusing part. My simple and non-laywer understanding is that you can't just change the terms of the licence like that, if SE says the content is CC licensed, that's it. Anything else SE says is meaningless. Commented Jun 5, 2015 at 22:11
  • 8
    But what the blog post and the TOS do is add a tiny little clause to the CC license, mostly the stuff about the "nofollow" attribute. This is not covered by the CC license in my understanding, and that is the actual issue here. There's no question that anyone using the content should link back to the post and mention who posted it. But doing SEO on this and requiring nofollow links is something entirely different. Commented Jun 5, 2015 at 22:14
  • 4
    "There's no question"... Except, there is. You can't look at this in isolation, out of time and context. No one sat down and said, "I don't like the attribution requirements in CC, so I'm writing my own" - the plain-English, web-specific requirements found on the blog only exist because there was "confusion" over how to apply the ones in the license. That's not some obscure historical fact, it's stated up-front in the post if anyone bothered to read it. There is no SE-BY-SA; there's a license, and a blog post explaining how to apply the license requirements.
    – Shog9
    Commented Jun 5, 2015 at 23:36
  • 11
    @Shog9 You make it sound like the blog post is only an explanation, but the nofollow stuff is definitely an addition to the licence. Either that or it should be edited to sound like a suggestion. Commented Jun 6, 2015 at 8:29
  • 2
    I'm pointing out the context in which the blog post was written and why it was (and still is) important, @curiousdannii - nothing more. I fully understand the temptation to try to divide attribution rules into a bunch of discrete pieces that can be interpreted and applied in isolation without regard for intent... But that is neither possible nor advisable. The intent of the license is clear: to ensure that authors are given credit for their work. The blog post specifies how to do this on The Internet. You'll find nothing objectionable in the latter unless you're looking to violate the former.
    – Shog9
    Commented Jun 6, 2015 at 16:38
  • 4
    @Shog9 I mostly agree, but I'm not sure it's true that using "nofollow" counts as "not attributing" a source. Commented Jun 6, 2015 at 20:17
  • In the context of the blog post, nofollow is but one of a number of examples of bad faith "linking but not really" tricks cited, @kyle. Folks get hung up on it, but redirects/tinyurls/etc. are just as shady (if not more so).
    – Shog9
    Commented Jun 6, 2015 at 20:45
  • 2
    @Shog9 But a "nofollow" link really is the same URI, isn't it? (I don't know much about URIs or nofollow.) Commented Jun 6, 2015 at 20:54
  • 1
    I think we should take this to the new Law! Commented Jun 6, 2015 at 23:27
  • 12
    I don't really see how these questions about "the spirit of the license" are germane on the TOS page. The TOS page should say what the license is, not what SO wishes it were. Suggestions about how to attribute are great, but you can't just pretend the license is CC and then say you have to do all that other stuff in order to follow the license. Just because SO really really wishes people wouldn't do certain things doesn't mean those restrictions are part of the license, and just because nice people don't need to know the details of the license doesn't mean it's ok to state them incorrectly.
    – BrenBarn
    Commented Jun 7, 2015 at 0:50
  • 7
    I think this answer is presenting the exact same problem the linked blog post is presenting: this is not representative of the license supposedly in use. Further, I would suggest that linking a rather rambling blog post in the context of a legal disclaimer weakens any legal claims based upon that license.
    – user295616
    Commented Jun 7, 2015 at 7:46
  • 3
    The ToS is not a content license, @Bren. The license concerns the rights and conditions granted by authors to those using their work; the ToS is the conditions by which we are all allowed to use these sites. Stack Exchange could close its doors tomorrow, disappear from the face of the earth and its ToS would go with it, but the license would remain in effect. We can (and do) take action against sites that access the network but violate the ToS; that's the point of the second blog post I referenced and the only connection the ToS has to the rest of this.
    – Shog9
    Commented Jun 7, 2015 at 15:05
  • @Shog9: I see. So if Person A were to make copies of SE data available (e.g., by mirroring the data dump), and Person B got the data from Person A, and then Person B did all sorts of nefarious quasi-attributions that violate the spirit of the license but not the letter, then SE would have nothing to say about that (since Person B did not get the data from SE itself, and so is not subject to the TOS)? That is, the difference is that the license transfers to anyone who uses the content, but the TOS only applies to those who get the content directly from SE?
    – BrenBarn
    Commented Jun 7, 2015 at 17:51
  • 3
    Not quite, @Bren (what you're describing almost certainly happens every time you request a page via HTTP...). Think of it this way: if you're taking someone's post and displaying it somewhere, your concern is limited to the license you received from that post's author(s). If you're scraping this website, then you have to be concerned about the people operating the website as well; they don't have to go to court to stop you from using the website. Think: restaurant owner can't tell you what you do with takeout in your own home, but they can refuse to serve you or kick you out of the restaurant.
    – Shog9
    Commented Jun 8, 2015 at 19:29

I asked about this on the Law site and @chapka pointed out clause 8(e) in the CC BY-SA 3 license:

This License constitutes the entire agreement between the parties with respect to the Work licensed here. There are no understandings, agreements or representations with respect to the Work not specified here. Licensor shall not be bound by any additional provisions that may appear in any communication from You. This License may not be modified without the mutual written agreement of the Licensor and You.

This is an "integration clause", and its effect is that there can be no further restrictions than what the license itself says. So Stack Exchange is not allowed to add further restrictions, the blog post is unenforceable, and it should not be referenced in the footer.

  • 7
    Forget not enforceable, it's a blatant violation of the CC trademark usage terms. They even address this exact situation: "We also advise against modifying our licenses through indirect means, such as in your terms of service.".
    – user295616
    Commented Jun 1, 2016 at 20:23
  • 2
    Well done on actually answering the question asked. Shog makes good points, but he only explains why that blog post was written, not whether it is enforceable.
    – Wildcard
    Commented Oct 30, 2018 at 20:11

From the licence section 4c:

If You Distribute, or Publicly Perform the Work or any Adaptations or Collections, You must, unless a request has been made pursuant to Section 4(a), keep intact all copyright notices for the Work and provide, reasonable to the medium or means You are utilizing: (i) the name of the Original Author (or pseudonym, if applicable) if supplied, and/or if the Original Author and/or Licensor designate another party or parties (e.g., a sponsor institute, publishing entity, journal) for attribution ("Attribution Parties") in Licensor's copyright notice, terms of service or by other reasonable means, the name of such party or parties; (ii) the title of the Work if supplied; (iii) to the extent reasonably practicable, the URI, if any, that Licensor specifies to be associated with the Work, unless such URI does not refer to the copyright notice or licensing information for the Work; and (iv) , consistent with Ssection 3(b), in the case of an Adaptation, a credit identifying the use of the Work in the Adaptation (e.g., "French translation of the Work by Original Author," or

This is the relevant part of the CC license as far as I can tell:

"Screenplay based on original Work by Original Author"). The credit required by this Section 4(c) may be implemented in any reasonable manner; provided, however, that in the case of a Adaptation or Collection, at a minimum such credit will appear, if a credit for all contributing authors of the Adaptation or Collection appears, then as part of these credits and in a manner at least as prominent as the credits for the other contributing authors. For the avoidance of doubt, You may only use the credit required by this Section for the purpose of attribution in the manner set out above and, by exercising Your rights under this License, You may not implicitly or explicitly assert or imply any connection with, sponsorship or endorsement by the Original Author, Licensor and/or Attribution Parties, as appropriate, of You or Your use of the Work, without the separate, express prior written permission of the Original Author, Licensor and/or Attribution Parties.

This is the relevant part of Jeff's blog post:

So let me clarify what we mean by attribution. If you republish this content, we require that you:

  1. Visually indicate that the content is from Stack Overflow or the Stack Exchange network in some way. It doesn’t have to be obnoxious; a discreet text blurb is fine.
  2. Hyperlink directly to the original question on the source site (e.g., https://stackoverflow.com/questions/12345)
  3. Show the author names for every question and answer
  4. Hyperlink each author name directly back to their user profile page on the source site (e.g., https://stackoverflow.com/users/12345/username)

By “directly”, I mean each hyperlink must point directly to our domain in standard HTML visible even with JavaScript disabled, and not use a tinyurl or any other form of obfuscation or redirection. Furthermore, the links must not be nofollowed.

Bullet points 1-3 seem to be covered by the CC license. The "to the extent reasonably practicable" part of the licence should be integrated for the URL part, though.

Bullet point 4 is not covered by the license as far as I can tell. The addendum about nofollow is also not covered in the licence. SE is certainly free to suggest their preferred method of linking back, but I think it is deceptive to suggest that the licence actually requires this.

I agree that the blog post is problematic and should be changed. A non-legalese version of the attribution part of the CC license would be a good replacement.

  • 5
    I imagine one could make an argument that if they're providing a redirect link that they're not including the actual URL associated with the post. Providing a URL that can allow you to get to the real URL isn't actually providing the real URL. The whole "nofollow" thing though is clearly not something in the actual licence terms though.
    – Servy
    Commented Jun 5, 2015 at 15:47
  • @Servy That's a good argument, and that part doesn't really bother me anyway. Commented Jun 5, 2015 at 16:07

Not the answer you're looking for? Browse other questions tagged .