[...] might have been surprised when headlines began appearing last year suggesting that Google and its fellow tech giants were threatening everything from our economy to democracy itself. Lawmakers have accused Google of creating an automated advertising system so vast and subtle that hardly anyone noticed when Russian saboteurs co-opted it in the last election. Critics say Facebook exploits our addictive impulses and silos us in ideological echo chambers. Amazon's reach is blamed for spurring a retail meltdown; Apple's economic impact is so profound it can cause market-wide gyrations. These controversies point to the growing anxiety that a small number of technology companies are now such powerful entities that they can destroy entire industries or social norms with just a few lines of computer code. Those four companies, plus Microsoft, make up America's largest sources of aggregated news, advertising, online shopping, digital entertainment and the tools of business and communication. They're also among the world's most valuable firms, with combined annual revenues of more than half a trillion dollars.

In a rare display of bipartisanship, lawmakers from both political parties have started questioning how these tech giants grew so powerful so fast. Regulators in Missouri, Utah, Washington, D.C., and elsewhere have called for greater scrutiny of Google and others, citing antitrust concerns; some critics have suggested that our courts and legislatures need to go after tech firms in the same way the trustbusters broke up oil and railroad monopolies a century ago. But others say that Google and its cohort are guilty only of delighting customers. If these tech leviathans ever fail to satisfy us, their defenders argue, capitalism will punish them the same way it once brought down Yahoo, AOL and MySpace.

[...] There's a loose coalition of economists and legal theorists who call themselves the New Brandeis Movement (critics call them "antitrust hipsters"), who believe that today's tech giants pose threats as significant as Standard Oil a century ago. "All of the money spent online is going to just a few companies now," says [Gary Reback] (who disdains the New Brandeis label). "They don't need dynamite or Pinkertons to club their competitors anymore. They just need algorithms and data."