Like the oil barons at the turn of the 20th century, the data barons are determined to extract as much as possible of a resource that's central to the economy of their time. The more information they can get to feed the algorithms that power their ad-targeting machines and product-recommendation engines, the better. In the absence of serious competition or (until Europe's recently introduced General Data Protection Regulation) serious legal constraints on the handling of personal data, they are going to keep undermining privacy in their push to know as much about their users as they possibly canrnrnTheir dominance is allowing them to play a dangerous and outsize role in our politics and culture. The web giants have helped undermine confidence in democracy by underestimating the threat posed by Russian trolls, Macedonian fake-news farms, and other purveyors of propaganda. Zuckerberg at first dismissed claims that disinformation on Facebook had influenced the 2016 election as "pretty crazy." But Facebook itself now says that between June 2015 and August 2017, as many as 126 million people may have seen content on the network that was created by a Russian troll farm.rnrnrnWhy haven't antitrust regulators blocked deals to promote competition? It's mainly because of a change in US antitrust philosophy in the 1980s, inspired by neoclassical economists and legal scholars at the University of Chicago. Before the shift, antitrust enforcers were wary of any deals that reinforced a company's dominant position. After it, they became more tolerant of such combinations, as long as prices for consumers didn't rise. This was just fine with internet companies, since most of their services were free anyway. Critics say trustbusters exercised too little scrutiny. "Just because the web companies offer products for free doesn't mean they should get a free pass," says Jonathan Kanter, an antitrust lawyer at Paul Weiss.rnrnthanks to their vast wealth, fining them for any transgressions won't diminish their power.rnrnOne radical solution would be to break them up, just as the US government splintered the dominant Standard Oil monopoly in the early 1900s. Some progressive advocacy groups in the US have been running online campaigns with slogans like "Facebook has too much power over our lives and democracy. It's time for us to take that power back," and calling on the FTC to force the social network to sell Instagram, WhatsApp, and Messenger to create competition.rnrnSo how to curb the power of the data barons? Rather than waiting for legal battles that may or may not foster more competition, we urgently need to find ways to bolster rivals. That means reducing the vast chasm between the amounts of information held by the web giants and the rest. Regulation can help here: Europe's new data privacy regime requires companies to hold people's data in machine-readable form and let them move it easily to other businesses if they want to. This "data portability" rule will allow startups to get hold of more data quickly.rnrnrnSome argue that we need to think much more boldly-and not just with the big internet companies in mind. Viktor Mayer-Sch195182nberger, a professor at the University of Oxford, has proposed what he calls a "progressive data-sharing mandate" that would apply to all businesses. This would require a company that has passed a certain level of market share (say, 10 percent) to share some data with other firms in its industry that ask for it. The data would be chosen at random and stripped of all personal identifiers. Intuitively, the idea makes sense: the closer a company gets to dominating its market, the more data it would have to share, making it easier for rivals to compete by building a better product.