The Justice Department’s aggressive antitrust fight with Microsoft nearly two decades ago and even its attempt to block the software company Oracle’s acquisition of a rival several years later seem like relics of a forgotten era for the tech industry in the United States.

Europeans, however, have kept up tough scrutiny of the industry, as seen in the recent fine against Facebook and the continued examination of Google’s advertising and data collection practices. As Mark Scott writes, Amazon, Apple, Google and Microsoft have all become targets of long antitrust investigations in the past two decades.

And in an industry that depends so much on international customers, the laws of other countries can matter just as much as the regulations at home.