How Google Allegedly Monopolized the Ad Technology Market

Google has monopolized the technology used to buy and sell online display ads by restricting or eliminating the choices of its customers — both website publishers and advertisers — the US Justice Department alleged at a federal antitrust trial.

Antitrust enforcers have sought to illustrate how the Alphabet Inc. unit’s complex ad ecosystem works and the ways in which the company allegedly manipulated the features of its products and the rules of its auctions to its own benefit. Over the last two weeks at the Virginia trial, they accused Google of abusing its market power in three areas: sell-side tools used by websites, called ad servers; advertising exchanges; and buy-side tools used by advertisers known as ad networks.