The rise and rise of ad-blockers (and ad-blocker-blocker-blockers) is without parallel: 26% of Internet users are now blocking ads, and the figure is rising. It’s been called the biggest boycott in human history.

It's also something we've seen before, in the earliest days of the Web, when pop-up ads ruled the world (wide web), and users went to war against them.

In 1994, Hotwired (the defunct online adjunct to Wired magazine) displayed the first banner ad in Internet history. Forty-four percent of the people who saw that ad clicked on it. At the time, it felt like advertising had taken a great leap, attaining a conversion rate that bested print, TV, direct mail, or display advertising by orders of magnitude.

But it turned out that the click-rate on that Hotwired ad had more to do with novelty than any enduring persuasive properties of banner ads. Even as Web companies were raising millions based on the fabulous performance of early ads, the efficacy of those ads was falling off a cliff, with clickthrough rates plummeting to low single digits.

This created a desperate situation, where publishers needed to do something -- anything -- to goose their clickthrough rates.

Enter the Pop-Up Ad

That's when Ethan Zuckerman—then an employee at Tripod—invented the pop-up ad (he has since apologized). These ads spawned in new windows and were much harder to ignore—for a while. Human beings' response to stimulus tends to regress to the mean (the refrigerator hum gets quieter over time because you adapt to it, not because the decibel level decreases) and so pop-up ads evolved into ever-more virulent forms—pop-under ads, pop-ups with fake "close" boxes, pop-up ads that respawned, pop-up ads that ran away from your mouse when you tried to close them...

At the height of the pop-up wars, it seemed like there was no end in sight: the future of the Web would be one where humans adapted to pop-ups, then pop-ups found new, obnoxious ways to command humans' attention, which would wane, until pop-ups got even more obnoxious.

But that's not how it happened. Instead, browser vendors (beginning with Opera) started to ship on-by-default pop-up blockers. What's more, users—who hated pop-up ads—started to choose browsers that blocked pop-ups, marginalizing holdouts like Microsoft's Internet Explorer, until they, too, added pop-up blockers.

Chances are, those blockers are in your browser today. But here's a funny thing: if you turn them off, you won't see a million pop-up ads that have been lurking unseen for all these years.

Because once pop-up ads became invisible by default to an ever-larger swathe of Internet users, advertisers stopped demanding that publishers serve pop-up ads. The point of pop-ups was to get people's attention, but something that is never seen in the first place can't possibly do that.

How About No ?

The Internet is full of take-it-or-leave-it offers: click-through and click-wrap agreements that you can either click "I agree" on or walk away from.

As the online world has grown more concentrated, with more and more power in fewer and fewer hands, it's become increasingly difficult for Web publishers to resist advertisers' insistence on obnoxious tracking ads.

But Internet users have never been willing to accept take-it-or-leave-it as the last word in technological self-determination. Adblockers are the new pop-up blockers, a way for users to do what publishers can't or won't do: demand a better deal from advertisers. When you visit a site, the deal on offer is, "Let us and everyone we do business with track you in every way possible or get lost" and users who install adblockers push back. An adblocker is a way of replying to advertisers and publishers with a loud-and-clear "How about nah?"

Adversarial Interoperability

Adversarial interoperability occurs when someone figures out how to plug a new product or service into an existing product or service, against the wishes of the company behind that existing product or service.

Adblocking is one of the most successful examples of adversarial interoperability in modern history, along with third-party printer ink. When you visit a website, the server sends your browser a bunch of material, including the code to fetch and render ads. Adblockers throw away the ad parts and show you the rest, while ad-blocker-blocker-blockers do the same, and then engage in an elaborate technological game of cat-and-mouse in a bid to fool the server into thinking that you are seeing the ads, while still suppressing them.

Browsers have always been playgrounds for adversarial interoperability, from the pop-up wars to the browser wars. Thanks to open standards and a mutual disarmament rule for software patents among browser vendors, it's very hard to use the law to punish toolsmiths who make adblocking technologies (not that that's stopped people from attempting it).

Adversarial interoperability is often a way for scrappy new upstarts to challenge the established players—like the company that got sued by IBM's printer division for making its own toner cartridges and grew so big it now owns that printer division (!).

But adversarial interoperability is also a way for the public to assert its rights and push back against unfair practices. Take-it-or-leave it deals are one thing when the market is competitive and you can shop around for someone with better terms of service, but in highly concentrated markets where everyone has the same rotten deal on offer, adversarial interoperability lets users make a counteroffer: "How about nah?"

But for How Long?

Concentration in the tech industry—including the “vertical integration” of browsers, advertising networks, and video content under one corporate umbrella—has compromised the Internet's openness. In 2017, the World Wide Web Consortium published its first-ever "standard" that could not be fully implemented without permission from the giant tech and media companies (who have since refused that permission to anyone who rocks the boat). In publishing that standard, the W3C explicitly rejected a proposal to protect adversarial interoperability by extracting legally binding nonaggression promises from the companies that make up the consortium.

The standard the W3C published—Encrypted Media Extensions (EME), for restricting playback of video—comes with many dangers for would-be adversarial interoperators, notably the risk of being sued under Section 1201 of the Digital Millennium Copyright Act, which bans tampering with “access controls” on copyrighted works and holds out both criminal and civil liability for toolsmiths who traffic in programs that let you change the rules embodied by EME.

One driving force behind the adoption of EME was the ever-tighter integration between major browser vendors like Google, video distributors, and advertising networks. This created a lopsided power-dynamic that ultimately ended up in the standardization of a means of undoing the configurable Web—where the user is king. EME is the first crack in the wall that protected browsers from those who would thwart adversarial operability and take "how about nah?" off the table, leaving us with the kind of take-it-or-leave-it Web that the marketing industry has been striving for since the first pop-up ad.