At a very simple ethical level there is a clear problem with using an adblocker. There is, after all, a very clear understanding that ad providers are paying them for your access to the content. Put differently: You pay for the content by watching those ads (of which selling your privacy is often, though not always, a part). Unethical however hardly means directly unlawful/illegal, so I have often wondered about the legal mirror of those ethical rules.

Our hypothetical case

So, some ToS's explicitly have statements like

You agree not to alter or modify any part of the Service.

taken from the YouTube ToS. So let's assume our theoretical service has those as well as possibly even explicitly addressing adblockers. Note that I am not saying that the quoted statement is the best legal way of putting this, it's purely an example.

Now, let's say that a user uses this service for a year whilst an adblocker is running. Let's also say that the user has signed up for the service and explicitly consented the Terms of Service. Is there any way that the service could lawfully get this user to pay up for his usage of the service (the loss of income)? Or if not, is there any form of 'punishment' the user could face? (Beyond being blocked from the service, but he could also be blocked from the service even if he didn't use an adblocker if the service felt like it) And if yes, does it require such an explicit segment in the ToS or is this already a natural given?

PS. I have selected the as the main focus of the question, simply because it's most likely to get a quality answer, however if you also know how the same would work out in a western european country I would love it if an answer could include a very short rundown of that as well.

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    A couple thoughts short of an answer: In the ToS cited, a distinction is made between the Service and the Content. In that sense, an add blocker doesn't modify the 'Service'. And choosing to avoid third-party advertising content is not 'accessing content' -- quite the opposite. For this sort of thing to have a hope of working, content providers would have to host the ads directly themselves and make them part of the content platform. Which is also the technical workaround for blocking. But no one wants to actually do that for their own engineering and PR reasons.
    – daffy
    Commented Jul 25, 2015 at 13:43
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    Well, are you talking about the in-player ads, or the ads around a web page? I'm not sure about YT's video ads, in the player frame, but in most cases the ads pushed are coming from some other domain—the advertising company's network or their CDNs. Ad-blockers work by blocking third party content from known advertising sources, not by somehow magically hacking the internal code of every web-app out there that integrates advertising.
    – daffy
    Commented Jul 25, 2015 at 20:39
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    How ad blockers work is directly relevant to why they cannot be effectively countered by ToS.
    – daffy
    Commented Jul 25, 2015 at 20:53
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    Arguably, since none of the ads are served from the youtube.com domain, blocking them does not involve changing the website (which is defined as the Service).
    – March Ho
    Commented Jul 26, 2015 at 0:24
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    @MarchHo You seriously want to say that advertisements are not a part of the Youtube website? I mean, just because I host images from the amazon CDN on some websites doesn't mean those images aren't part of my website. Commented Jul 26, 2015 at 11:17

3 Answers 3


This is a complicated question because adblockers have grown increasingly complex in recent years. What it means to "block ads" from both a legal and technical perspective is more complex than it was just a few years ago.

First the broad strokes: It's not illegal to block ads.

Multiple court cases have defended users' rights to control the information that enters their computers / devices. You have the legal right to view or not view whatever you like.

But... that doesn't mean your use of an adblocker isn't in violation of US law.

The crucial issue with legality when it comes to adblockers is less about blocking ads, and more about circumventing a websites measures to defeat adblockers.

The US DMCA has strict wording regarding 'circumvention of access controls'. If a website has taken active measures to prevent access by adblocking users, and your adblocker circumvents those measures -- this is very likely a violation of the DMCA. The important point here is that the legal transgression isn't blocking ads. It's the circumvention of access controls which in attempt to limit access to adblock users.

There's a good write-up on this topic here:


Additionally, a website's "Terms of Use" agreement may address adblocking. As we all know, website ToU's are not always legally binding on the site visitor. But sometimes they are.

There's a good exploration of how to implement a ToU that addresses adblocking here:


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    I started running adblockers after CNN started serving malware. The sites that kick off people who block ads are also the ones most likely to be serving malware. You might want to reconsider your position.
    – Joshua
    Commented Oct 26, 2018 at 1:41

Specifically regarding Youtube, it would appear that it would be legal to use an adblocker, regardless whether it technically violates the ToS or not, as YouTube is browsable without any requirement of having to accept the ToS. If a user has not accepted the ToS, all videos are still viewable both on the main page and from links.

Clickwraps (as litigated in Feldman v Google) were held to be legally enforcable means of a contract, if the contract is not judged to be unconscionable, and is judged to be enforceable.

However, since Youtube only displays their TOS in a link in small print near the bottom of the page, which is not reachable unless you scroll all the way to the bottom past the videos, it would clearly appear that the ToS of Youtube is not a clickwrap, but instead a browsewrap. This has been litigated in Specht v Netscape

Because we conclude that the Netscape webpage did not provide reasonable notice of the existence of SmartDownload’s license terms, it is irrelevant to our decision whether plaintiff Fagan obtained SmartDownload from that webpage, as defendants contend, or from a shareware website that provided less or no notice of that program’s license terms, as Fagan maintains. In either case, Fagan could not be bound by the SmartDownload license agreement.

Since Youtube does not clearly provide reasonable notice of the ToS, it is highly likely that any legal challenges on violations of the Youtube ToS would be unsuccessful.

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    This entire answer makes an assumption that has clearly been dismissed since version 1 of the question "Lets also say that the user has signed up for the service and explicitly consented the Terms of Service.". Commented Jul 25, 2015 at 9:16

Is adBlocker modifying the service? AdBlocker is a browser modification that tell the browser not to display this service or load this service. Google delivers the content, then your browser is in charge of displaying the content.

Many Web browsers don't display ad's without the aid of addOns like AdBlock.

  • Web Browsers like Lynx don't display ad's because they are text only.
  • Turning off images or JavaScript in any browser.
  • Browsing via accessibility software like a screen reader.
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    So you're saying that a ToS can not limit in any way the things that the user is allowed to do with the Content? Because that's provably wrong. Commented Jul 25, 2015 at 17:22
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    @DavidMulder, no im not saying that the user is allowed to do anything they want with the content. But that Google (in this case) serves the content, and they can not control how your browser renders the content. And for the user causes loss of income, you are correct on that, see [my other answer on that]( law.stackexchange.com/a/927/450 )
    – Jdahern
    Commented Jul 25, 2015 at 17:47
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    "Theoretically" you can put almost anything in your ToS. It may not be enforceable. ("(1)[a][5]By accessing the SERVICE you agree to RUMPLESTILSKIN'S adoption of YOUR FIRSTBORN SON.)" If preventing ad-blocking by ToS was workable, it would already be a widespread practice.
    – daffy
    Commented Jul 25, 2015 at 20:51
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    That starts to get into contract law I believe. With ToS, companies can place whatever they want in there, but all parts of the ToS may not be enforceable. AFAIK, there has not been any case that has shown that allowing access to certain browsers enforceable.
    – Jdahern
    Commented Jul 25, 2015 at 20:56
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    It's probably not illegal, as everyone here is saying. It's clear you want it to be, but that's not how it works.
    – daffy
    Commented Jul 26, 2015 at 12:08

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