At Google antitrust trial, documents say one thing. The tech giants witnesses say different [Video]

ALEXANDRIA, Va. — The judge who will decide whether Google holds a monopoly over technology that matches buyers and sellers of online advertising must choose whether to believe what Google executives wrote or what they have said on the witness stand.

The Justice Department is wrapping up its antitrust case against Google this week at a federal courtroom in Virginia. The federal government and a coalition of states contend Google has built and maintained a monopoly on the technology used to buy and sell the ads that appear to consumers when they browse the web.

Google counters that the government is improperly focused on a very narrow slice of advertising – essentially the rectangular banner ads that appear on the top and along the right side of a publisher’s web page – and that within the broader online advertising market, Google is beset on all sides from competition that includes …