FOR THE BETTER part of a year, the tech world has wondered what, exactly, the Department of Justice’s long-rumored antitrust case against Google would look like. Now we have an answer. The department filed a complaint against Google on Tuesday, triggering the most significant antitrust case since the US sued Microsoft in the 1990s. At the heart of the government’s case is Google’s use of exclusive contracts to become the default search engine on other companies’ browsers and devices. These techniques, the DOJ argues, helped Google transform from “a scrappy startup” to “a monopoly gatekeeper for the internet” that unfairly blocks the path of would-be rivals.