Google has been found guilty of violating antitrust law. Northeastern University researchers looked at Google's own argument—and still found the tech giant dominates nearly every part of the search market.

In what could be the most significant ruling in antitrust law of the modern era, a federal judge ruled Monday that Google illegally used its monopoly in online search to squash competition and hurt innovation.

During the trial, the Justice Department argued that Google's dominance of the search market hurt the market at large.

Google pursued a different tactic, arguing that it doesn't just compete with other search engines like Bing, it competes with anything that has a search function, from Amazon to Travelocity. With all that competition, how could Google have a dominant market position?

Researchers at Northeastern University decided to answer that question.

"We went, 'We're going to take Google at their word and say maybe they do compete against everybody. What does that actually look like?'" says Christo Wilson, a professor of computer science at Northeastern. "Guess what? It still looks like Google's world."

In a recently published study in the Proceedings of the International AAAI Conference on Web and Social Media, the researchers recruited a sample of U.S. residents and gave them a browser extension that allowed them to see everything the study participants did in their browser.

By observing where the participants went online every time they opened their browser, the researchers were able to break down online searches into 30 primary categories.

Even with all the additional competition Google faced, it still received more than 50% of searches in 21 out of 30 categories, which included navigation, shopping, real estate, health and wellness, dining and travel. The areas where Google wasn't the dominant search option included categories like real estate, where Zillow dominated, and shopping, where Amazon reigned supreme.

"Even if you take Google at their word that they face competition from all verticals, they still appear to be dominant in the market," Wilson says. "They don't win 100% of the time, but they win a majority of the time."

It doesn't help that Google has methodically made itself the default search option, even on other browsers. It was revealed during the antitrust trial that Google spent $26.3 billion in 2021 to become the default search engine on two other major browsers, Safari and Firefox.

That fact played a huge role in the ruling against Google that could reshape the tech industry, Judge Amit P. Mehta of the U.S. District Court for the District of Columbia said in his ruling.

"If that's what it takes for somebody to dislodge Google as the default search engine, wouldn't the folks that wrote the Sherman [Antitrust] Act be concerned about it?" Mehta said.

Additionally, in 24 out of the top 30 search categories, people started their search on Google. Wilson says it speaks to Google's "gatekeeping power," which goes beyond just where you start searching for shoes or plane tickets. In a previous study, Wilson showed Google's ability to steer user behavior through the design of its search page.

"People are starting at Google, and yeah, you might go on to do a search on Amazon, but you started at Google and that gives them enormous power to shape what you're shown and ultimately where you go," Wilson says. "If they want you to have terminal searching and they just show you answers from [Google AI chatbot] Gemini, they can push that and dramatically alter peoples' behavior at very large scales very quickly."

The researchers' findings come at a time when not just Google but Meta, Amazon and Apple, the biggest tech companies in the world, are facing a series of landmark antitrust cases. The ruling against Google isn't necessarily an indication of the future—each case is different—but Wilson says where there is monopoly, there are questions worth asking.

"I will caveat all this by saying that having monopoly power is not necessarily anticompetitive," Wilson says. "Monopoly by itself is not illegal in this country, but it certainly raises questions."

More information: Desheng Hu et al, Market or Markets? Investigating Google Search's Market Shares under Vertical Segmentation, Proceedings of the International AAAI Conference on Web and Social Media (2024). DOI: 10.1609/icwsm.v18i1.31340