Should tech companies be worried about DoJ's antitrust review?

Action may finally be taken over claims Facebook, Google Apple and Amazon have monopolised chosen fields

The US Department of Justice (DoJ) has announced a wide-ranging antitrust review of "market-leading online platforms", suggesting that long-awaited action may finally be taken against some of the world's largest companies.

But the confirmation of the investigation is sparse on detail, revealing only that the review "will consider the widespread concerns that consumers, businesses and entrepreneurs have expressed about search, social media, and some retail services online".