Adblockers don't break the law. Except when they do.


Is it illegal to block ads?

According to multiple court cases, the choice to filter your own http requests is legal and ultimately up to you. It’s your computer (or your mobile device). You have the right to decide which content and scripts enter your system.
The best way to understand this right is that adblockers are basically “selective downloaders“. They decide which content to download and view, and which content to ‘not download’ and ignore. That simple choice has been protected multiple times in multiple court decisions.
But while that means ‘not downloading ads’ is inherently legal. It may not mean all adblockers are operating legally.
The problem is that “selective downloading” isn’t all adblockers are doing. The rabbit hole goes far deeper than just ‘not downloading advertising‘…

Adblockers and Anti-Circumvention laws

Adblockers aren’t just blocking ads.
Adblockers also employ sophisticated circumvention technologies that evade the defensive measures employed by publishers. This crucial feature marks an important legal line in the sand.
“Anti-adblock” or “access control” technologies (like BlockAdblock) restrict access to the copyrighted content of websites so that readers can access content only in a manner which the publisher approves of.
prevent access
Specifically, access control technologies like BlockAdblock restrict browsers equipped with adblock plugins from accessing a website’s content. Users who attempt to selectively download only the copyrighted content, without the accompanying advertising may be barred from access.
And here’s the rub:
While blocking ads has been deemed legal in court, circumvention of access controls is expressly against the law in Europe, the United States and in all signatory-nations of the World Intellectual Property Organization’s Copyright Treaty.
In other words: You’re free to block ads but as soon as an access-control technology enters the picture, you may not be within your rights to attempt to circumvent it by technological measures.
And that’s exactly what so many adblockers attempt to do — with varying levels of success, depending on the adblocker and the anti-adblock technology being deployed in any given case.
adblock circumvention

What laws are being broken?

Anti-circumvention laws in the US, EU and countries who have signed the WIPO treaty are quite similar.


European national laws must reference Article 6 of the EU Directive 2001/29/EC

  1. Member States shall provide adequate legal protection against the circumvention of any effective technological measures, which the person concerned carries out in the knowledge, or with reasonable grounds to know, that he or she is pursuing that objective.
  2. Member States shall provide adequate legal protection against the manufacture, import, distribution, sale, rental, advertisement for sale or rental, or possession for commercial purposes of devices, products or components or the provision of services which:
    • (a) are promoted, advertised or marketed for the purpose of circumvention of, or
    • (b) have only a limited commercially significant purpose or use other than to circumvent, or
    • (c) are primarily designed, produced, adapted or performed for the purpose of enabling or facilitating the circumvention of, any effective technological measures.
  3. For the purposes of this Directive, the expression ‘technological measures’ means any technology, device or component that, in the normal course of its operation, is designed to prevent or restrict acts, in respect of works or other subjectmatter, which are not authorised by the rightsholder…

In other words, it’s not okay to circumvent technological measures which restrict access to a work.  It’s also not okay to manufacture or distribute products whose purpose is to circumvent access controls. And it’s up to the publisher / rights-holder to decide what the terms of said access are. 

United States

Likewise, across the pond in the USA, the Digital Millennium Copyright Act (DMCA) includes several sections relevant to the circumvention of website access controls:
Section 103 of the DMCA includes this very clear language:

No person shall circumvent a technological measure that effectively controls access to a work protected under this title.

And “technological measure” is defined as follows:

(3)(B) a technological measure “effectively controls access to a work” if the measure, in the ordinary course of its operation, requires the application of information, or a process or a treatment, with the authority of the copyright owner, to gain access to the work.

Clearly, any anti-adblock defense used to protect website content falls under the description of a “technological measure” requiring a process or treatment to gain access to the work.  (That “process or treatment” being the detection of no adblocker, in this particular case).
For more information on how adblockers violate the DMCA see the previous post: Is Adblock Plus violating the DMCA

It’s not adblocking that’s illegal. It’s the circumvention of ‘technological measures’ that is.

Certainly, this doesn’t mean that blocking ads is illegal. But it does strongly suggest that the additional layer of technology employed by current-generation adblockers to circumvent the technological defenses of adblock-detection scripts is illegal.
Anti-circumvention law was enacted for a purpose.
That purpose is to protect “remuneration schemes” and to”foster substantial investment in creativity and innovation”, to use the opening language of the EC Directive.

A harmonised legal framework on copyright and related rights … will foster substantial investment in creativity and innovation, including network infrastructure, and lead in turn to growth and increased competitiveness of European industry, both in the area of content provision and information technology and more generally across a wide range of industrial and cultural sectors. This will safeguard employment and encourage new job creation.

Somewhere along the line that primary purpose appears to have been replaced with something less sustainable, and a whole lot less legal.

39 Replies to “Adblockers don't break the law. Except when they do.”

    1. Not all circumvention is illegal. Only those specific kinds of circumvention described in applicable law are illegal. In the United States, DMCA (17 USC 1201) bans only circumvention of access control around a copyrighted work, and CFAA (18 USC 1030) bans knowingly accessing information stored on a computer on the other side of an interstate network in violation of agreed-upon terms of use. BlockAdblock just withholds authorization if it 1. runs and 2. detects that ads fail to load. Which of these does it violate, and in what manner?

      1. > ,DMCA (17 USC 1201) bans only circumvention of access control around a copyrighted work”
        Websites contain copyrighted work.

        1. Let me try to make it plainer: You claim that anti-anti-adblock violates the DMCA because anti-adblock controls access to a copyrighted website. Your claim looks interesting enough to try in court. But Raoulista claims that anti-adblock itself circumvents the user’s adblock. I dispute Raoulista’s claim that anti-adblock violates the DMCA because there is no copyrighted work to which adblock controls access.

          1. Like I said, merely blocking the URL of the anti-adblock script, on your router, does not violate the law, since you are not hacking into their machines.
            In order to be in violation of the DMCA of CFAA, you would have to hack into the website. Blocking a URL is not hacking, either under the DMCA or CFAA

        2. You do know by creating this crap certain groups will take notice and destroy your priveleges only because you keep blocking those users only because you act like a bunch of childeren. We bend the law, thus we do not break it. You guys break the law with false accusations to create a thing that works best for you, but by blocking people you create a gap that results into site owners loser people to watch the streams, resulting into a massive debt that eventually ends the site into having to close.
          So here is my advice, f* off with that policy.

  1. This post glossed up over many legal technicalities. There are more requirements for something to be an “effective access control” and etc. Blockadblock script does NOT detect adblockers, it only detects some elements were hidden or some requests were blocked. Also, that access control prevention by technological measure is one of subtle parts of copyright laws, this can be different from countries to countries. I regard this post as an unsubstantiated claim just like how Hans’ claim that adblock detection is illegal was.

  2. This article is glossing over many legal technicalities about “anti-circumvention”. There are more legal requirements for something to qualify as an effective technological measure, and this is one of subtle parts of a copyright law; legal regulations on access control by technological measures differs from countries to countries.
    Note that Blockadblock does NOT detect adblockers – it only detects whether some elements were hidden or some requests to ad servers returns errors, which can be caused by other software or even at server-side; Also it does not encrypt the main copyrighted content; there are many ways to view an webpage ad-free such as a ‘reader view’ feature provided by browsers. Thus, there are many legal difficulties for such anti adblock scripts to qualify as ‘technological measures’.
    I regard this post as an unsubstantiated claim, just like how Hans’ claim that detecting adblockers is illegal in EU was.
    +) This comment was deleted once by someone… well, it’s obvious who did it 🙂

    1. Thanks for your comment. I think if you read the other posts on this site you’ll find that I am the very first one to say that BlockAdblock does not directly detect adblockers. That’s been my argument from day one in regards to the European ePrivacy Directive.
      For example, I wrote:
      > “Anti-adblock scripts merely guess at the existence of an adblock plugin based on imputed information about how a webpage has been rendered within the browser. In other words, adblock detection scripts don’t “report”. They “infer”.
      Secondly, please identify the technicalities that are being “glossed” over. I note that your argument consists of a claim that there are some important points being left out, **and then you proceed to leave them out yourself**.
      This is a conversation. Let’s have one. The EU directive seems to me to apply. If it doesn’t I’d love to hear why you think it doesn’t. I’m familiar with copyright law. But not this mysterious point you seem to be referencing about a legal definition of an “effective technological measure” which contradicts my points above. Please direct me to that. Thanks.
      You note that BlockAdblock “does not encrypt the main copyrighted content”. Yes, and? Full encryption of the copyrighted content is not among the qualifications or requirements for an anti-access control. I’m not sure what (if any) legal concept you are referencing. Can you cite this?
      You’re claiming both an incorrect portrayal of the law, and a degree of complexity which refutes what I’ve said above. I’m all ears. Specifics please.

      1. So this is your reply after deleting my comment once. That’s a huge improvement! Although you’re hastily concluding that my claim is incorrect, if not falsely. This is not a good attitude in listening to other’s opinion 🙂
        The main legal point that I see lacks in this post is whether anti-adblock solutions qualifies as ‘technological measures”. You just say,
        > Clearly, any anti-adblock defense used to protect website content falls under the description of a “technological measure” requiring a process or treatment to gain access to the work. (That “process or treatment” being the detection of no adblocker, in this particular case).
        This is where you are clearly glossing over legal complications. In this very sentence, you said “process of treatment = detection of no adblocker”, which contradicts what you said above, “BlockAdblock does not directly detect adblockers”.
        Also, most copyright laws protect only those “effective” technological measures.
        In case of US, see
        > No person shall circumvent a technological measure that effectively controls access to a work protected under this title.
        For example, if you put a simple scriptlet to disable context menus in your website, it cannot qualify as an effective technological measure to prevent making an unauthorized copy of copyrighted contents. Examples of ‘effective’ technological measures would be DRM which fully encrypts the content. I don’t see any arguments about this point. If you have any reason to believe that anti-adblock scripts such as blockadblock falls into the category of effective technological measures, please supply it. I am interested in this matter.
        Lastly, all of your argument won’t apply in a country where I live, because it does not legally protect technological measures for access control. We does protect technological measures to prevent making of unauthorized copy, but we regards access control as a pursuit of individual benefit which doe not need to be protected by law. What anti-adblock scripts are trying is access control, so it is not protected by our copyright law. This is what I meant when I said it may differ from countries to countries. What will you do in this case?

        1. You are taking the term “detection” solely to mean “direct detection” which has a literal technological implication under the ePD. “Detection” is also the term used to describe the *effective* result — which is to detect the *presence* of an adblocker via indirect means. (Notably, detecting changes to the DOM). Context is important.
          Read the other posts on this blog and you will find this discussed, and this distinction made many times.
          Are you in the EU? It’s hard to understand how your point about “your country” applies to this article without knowing what country you’re in. If you’re not: In what way does your specific (non-US / non-EU) national case represent a rebuttal to the points above which deal with laws in the US & EU?
          Your other points are interesting corollaries but do not refute the points in the post. To be clear: Were there (hypothetically ) a distributed product whose sole purpose was to remove scriptlets that prevent copying text, that hypothetical product *may indeed also run counter to anti-circumvention law* in the US, EU and other WIPO signatory nations. However that isn’t being argued here as it’s a hypothetical product and an entirely separate case. (?!).
          I also think you are intentionally misunderstanding the term “effective”. But that of course should be debated in court. I hope one day it is.

          1. I’m not intentionally doing anything, it’s just how law is. You should face it, although it may not be favorable to your ** intention ** Oh, now it’s clear that you haven’t aware about this point, if not intentionally avoiding it, that the law only protects effective technological measures.
            “effectiveness” is important in determining whether some technological measure should be protected or not, and without a solid argument on it, your statement that “BlockAdblock and other anti-adblock systems are technological measures” and “adblockers circumventing anti-adblock system are illegal”, would be vacuous.
            My argument about detection mechanism also strengthens that access-control by means of indirect detection is not effective. By saying “process of treatment = detection of no adblocker”, you imply that it detects adblockers in an effective way, which in fact can be caused by server-side errors, do-not-track features integrated in browsers, and other browser extensions like Stylish. I agree that this should be debated in court. But until then, you should stop spreading intentionally misunderstood interpretation of the law.

          2. Not so. It is easily provable that adblockers are intentionally circumventing anti-adblock measures with purpose-built features. Without the addition of those features, access is impossible. Efficacy speaks for itself in those cases.
            The false positives you mention are irrelevant to the intent (or the actual result) of built-to-circumvent adblockers like Adblock Plus and others.
            This is without question (and by their own words) “intentional circumvention” of a technological anti-access control measure, and the clear distribution of a product whose purpose is circumvention.

          3. The following are simple policies that an add-on can implement. Which ones are “built-to-circumvent”?
            A. Do not load anything (images, scripts, etc.) from third-party domains
            B. Do not load SWF from hostnames other than those chosen by the user
            C. Do not load video content types from URL prefixes other than those chosen by the user

          4. Uh… Did you even read the article? None of those constitutes circumvention. Adblocking is legal, as is stated above. Circumvention of anti-Adblock scripts is illegal.

          5. Certain parts of the entertainment industry have historically held a
            very broad definition of “circumvention”. So I was asking how to avoid not only circumvention but also the appearance of circumvention while fighting ad misbehavior.

          6. Not if you block the URL, at the router level, where the scripts are loaded from it is not. As a network admin, you have the right to block any URL or web address you wish, including anti-adblock scripts.
            Blocking, which will knock out anti-adblock scripts on many sites, is no different than blocking the ads themselves, it is fully legal to do so.

      2. However, blocking the URL, at the router level, that prevents anti-adblock scripts from even being loaded, does not violate the DMCA, since merely blocking a URL on your router is not considered hacking under either the DMCA or CFAA.

  3. Ok so if adblockers are breaking the law how come YOU GUYS are not breaking the law by anti-circumvention of my ADBLOCK!

    1. It is not affecting the use of the software at all, it’s just selectively choosing to prevent access to some users of a website – which is the right of any website owner.

      1. Same thing as when a network operator chooses to block the URL which loads the URL of the detector. they are not affecting the way the software runs on the server, and blocking access to a URL does not violate any laws

  4. When will this end? AdBlock, BlockAdBlock, BlockBlockAdBlock, BlockBlockBlockAdBlockAdBlockBlocker. I believe that the answer is for advertisers to be creative and entice users to watch their ads! Offer discounts, Promos, etc. Ensure that the ad content does NOT block the information, nor does it visually or audibly disturb the user. I find it offensive when an ad flashes on and off repeatedly next to, over or under material that needs the users full and undivided attention.

  5. If ad blockers are breaking the law, then how do malicious ads that execute scripts secretly, or social media buttons and advertising scrips (like AdSense, among others) that track the user without his or her knowledge or consent don’t? I get that certain aspects of intellectual property laws are indeed broken by circumvention use, but the right to privacy is commonly considered to be a universal human right.

  6. It depends on how the circumvention is done. One method that does not violate the DMCA is to merely block the URLs od the detector scripts. Merely blocking a URL on your router, does not violate the law. If it did, The “web ads” category on all the major filtering softwware vendors would be illegal.
    So all you corporate network admins reading this, who choose to, say, block, which will knock out AdBlock detection on many websites, are not violating any laws, since the network operators have the right to block any network address they wish.
    BlockAdBlock is the only AdBlock in the world I have found that cannot be defeated by this measure, since it does not rely on loadinga Java or CSS script.
    Since you are blocking a URL, and hacking the AdBlock detection script directly, this does not violate the DMCA.

  7. If I create an app . Or book that blocks out browsers that have ad block enabled and someone tries to circumvent that to gain access that sounds like theft . But the majority of people don’t feel that way because they believe that if it’s on a website no matter who created it belongs to them.
    I would love to see that happen in someone’s home but I’m not worry too much since I don’t work as much online anymore so I give nothing away free now… everything is paid.
    I do market to a different audience which is older versus under 20. The under 20 or under 25 age group are more likely to break a company meaning they would not be sustainable weather be a developer, game developer, app developer or journalist they’re not sustainable so now I just ignore them.

  8. Thankfully, I can bypass this useless shit and write this by shrinking the window small enough or by using an anti-antiadblock.

  9. You know what? FORCE A SENSIBLE SET OF STANDARDS ON ADVERTISERS AND PEOPLE WOULDN’T BLOCK ADS. The reason people block ads isn’t because they don’t like ads or maliciously want to deprive people of money. It’s because the ads are huge, loud, invasive, intrusive, sometimes disguised as not advertising (which should be considered fraudulent)… when ads INTERFERE with a person’s ability to engage the content which they’ve requested, it causes them to go elsewhere for similar content (thus depriving the publisher of income) or to install adblockers (thus depriving the publisher of income).
    When you add in the ridiculous privacy violations that ads are often capable of and intended for, as well as the fact that so many ad services *do not seem to police the ads they push* and thus serve malicious code, you can see why people are anti-ads.
    To put it succinctly: ADVERTISERS ARE THEIR OWN PROBLEM.

  10. Actually, according to the Eu, BlockAdblock is illegal, without first getting consent to check on plugin use. Nice try though 😀

  11. I think this is unfair. The advertisers will still be selling their products and services at an increased price to recuperate advertising costs. People who use ad-blockers will be charged these higher prices just like anyone else, except they don’t have access to many websites.
    And advertising on the net and TV is both unethical and incredibly irrational. It should be banned and people pay for the content directly.

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