Karina Montoya shares five takeaways from the initial weeks of the Google ad tech monopoly trial in Tech Policy Press.

The antitrust trial against Google for allegedly illegally monopolizing digital advertising technologies (ad tech) enters its third week today. The case focuses narrowly on the industry that intermediates sales of open display ads — sold primarily on news websites — through three key products: publisher ad servers, ad-buying tools, and ad exchanges.

Last Friday, the Department of Justice rested its case after presenting 38 testimonies — 25 of them from witnesses who took the stand, with the rest being video and read-ins. Witnesses included representatives from news publishers, ad agencies, and ad tech companies, providing insight into the segments of the market in which Google is dominant.

This parade of witnesses depicted a digital advertising market in which it is difficult for publishers to escape their reliance on Google, rival publisher ad servers and ad exchanges can’t grow, and ads are transacted by Google in ways that reinforce its dominance.

Read five takeaways from the last two weeks at Tech Policy Press.

Follow Karina Montoya’s regular coverage of the trial here.