In March 2007, Google’s then senior executive in charge of acquisitions, David Drummond, emailed the company’s board of directors a case for buying DoubleClick. It was an obscure software developer that helped websites sell ads. But it had about 60 percent market share and could accelerate Google’s growth while keeping rivals at bay. A “Microsoft-owned DoubleClick represents a major competitive threat,” court papers show Drummond writing.

Three weeks later, on Friday the 13th, Google announced the acquisition of DoubleClick for $3.1 billion. The US Department of Justice and 17 states including California and Colorado now allege that the day marked the beginning of Google’s unchecked dominance in online ads—and all the trouble that comes with it.

The government contends that controlling DoubleClick enabled Google to corner websites into doing business with its other services. That has resulted in Google allegedly monopolizing three big links of a vital digital advertising supply chain, which funnels over $12 billion in annual revenue to websites and apps in the US alone.

It’s a big amount. But a government expert estimates in court filings that if Google were not allegedly destroying its competition illegally, those publishers would be receiving up to an additional hundreds of millions of dollars each year. Starved of that potential funding, “publishers are pushed to put more ads on their websites, to put more content behind costly paywalls, or to cease business altogether,” the government alleges. It all adds up to a subpar experience on the web for consumers, Colorado attorney general Phil Weiser says.

“Google is able to extract hiked-up costs, and those are passed on to consumers,” he alleges. “The overall outcome we want is for consumers to have more access to content supported by advertising revenue and for people who are seeking advertising not to have to pay inflated costs.”

Google disputes the accusations.

Starting today, both sides’ arguments will be put to the test in what’s expected to be a weekslong trial before US district judge Leonie Brinkema in Alexandria, Virginia. The government wants her to find that Google has violated federal antitrust law and then issue orders that restore competition. In a best-case scenario, according to several Google critics and experts in online ads who spoke with WIRED, internet users could find themselves more pleasantly informed and entertained.

It could take years for the ad market to shake out, says Adam Heimlich, a longtime digital ad executive who’s extensively researched Google. But over time, fresh competition could lower supply chain fees and increase innovation. That would drive “better monetization of websites and better quality of websites,” says Heimlich, who now runs AI software developer Chalice Custom Algorithms.

Tim Vanderhook, CEO of ad-buying software developer Viant Technology, which both competes and partners with Google, believes that consumers would encounter a greater variety of ads, fewer creepy ads, and pages less cluttered with ads. “A substantially improved browsing experience,” he says.

Of course, all depends on the outcome of the case. Over the past year, Google lost its two other antitrust trials—concerning illegal search and mobile app store monopolies. Though the verdicts are under appeal, they’ve made the company’s critics optimistic about the ad tech trial.

Google argues that it faces fierce competition from Meta, Amazon, Microsoft, and others. It further contends that customers benefited from each of the acquisitions, contracts, and features that the government is challenging. “Google has designed a set of products that work efficiently with each other and attract a valuable customer base,” the company’s attorneys wrote in a 359-page rebuttal.

For years, Google publically has maintained that its ad tech projects wouldn’t harm clients or competition. “We will be able to help publishers and advertisers generate more revenue, which will fuel the creation of even more rich and diverse content on the internet,” Drummond testified in 2007 to US senators concerned about the DoubleClick deal’s impact on competition and privacy. US antitrust regulators at the time cleared the purchase. But at least one of them, in hindsight, has said he should have blocked it.

Deep Control

The Justice Department alleges that acquiring DoubleClick gave Google “a pool of captive publishers that now had fewer alternatives and faced substantial switching costs associated with changing to another publisher ad server.” The global market share of Google’s tool for publishers is now 91 percent, according to court papers. The company holds similar control over ad exchanges that broker deals (around 70 percent) and tools used by advertisers (85 percent), the court filings say.

Google’s dominance, the government argues, has “impaired the ability of publishers and advertisers to choose the ad tech tools they would prefer to use and diminished the number and quality of viable options available to them.”

The government alleges that Google staff spoke internally about how they have been earning an unfair portion of what advertisers spend on advertising, to the tune of over a third of every $1 spent in some cases.

Some of Google’s competitors want the tech giant to be broken up into multiple independent companies, so each of its advertising services competes on its own merits without the benefit of one pumping up another. The rivals also support rules that would bar Google from preferencing its own services. “What all in the industry are looking for is fair competition,” Viant’s Vanderhook says.

If Google ad tech alternatives win more business, not everyone is so sure that the users will notice a difference. “We’re talking about moving from the NYSE to Nasdaq,” Ari Paparo, a former DoubleClick and Google executive who now runs the media company Marketecture, tells WIRED. The technology behind the scenes may shift, but the experience for investors—or in this case, internet surfers—doesn’t.

Some advertising experts predict that if Google is broken up, users’ experiences would get even worse. Andrey Meshkov, chief technology officer of ad-block developer AdGuard, expects increasingly invasive tracking as competition intensifies. Products also may cost more because companies need to not only hire additional help to run ads but also buy more ads to achieve the same goals. “So the ad clutter is going to get worse,” Beth Egan, an ad executive turned Syracuse University associate professor, told reporters in a recent call arranged by a Google-funded advocacy group.

But Dina Srinivasan, a former ad executive who as an antitrust scholar wrote a Stanford Technology Law Review paper on Google’s dominance, says advertisers would end up paying lower fees, and the savings would be passed on to their customers. That future would mark an end to the spell Google allegedly cast with its DoubleClick deal. And it could happen even if Google wins in Virginia. A trial in a similar lawsuit filed by Texas, 15 other states, and Puerto Rico is scheduled for March.