The federal antitrust trial against Google is examining claims that the company maintains an illegal monopoly in the online advertising sector, controlling billions of dollars in ad sales through its extensive ad technology. The Justice Department argues that Google's dominance allows it to rig automated auctions in its favor, depriving the publishing industry of substantial revenue. Witnesses in the trial are detailing the intricate processes of Google's ad auctions, which have evolved significantly over the past fifteen years to become highly personalized. While Google asserts that its practices enhance advertising quality and consumer experience, critics emphasize that such dominance stifles competition and innovation. A recent ruling has already classified Google as a monopolist in a separate case regarding its search engine, suggesting potential penalties or structural changes. This trial aligns with broader scrutiny from federal authorities on major tech companies like Apple and Amazon, highlighting ongoing concerns about monopolistic behaviors in the industry.