SAN FRANCISCO — Although Bazaarvoice has snapped up its chief competitor, plenty of alternatives remain in the market for online product ratings and reviews, the social commerce company’s industry expert testified Monday.

The Department of Justice sued earlier this year to undo Bazaarvoice’s 2012 purchase of PowerReviews, arguing that it created a virtual monopoly for the Austin-based company, which collects and displays feedback from consumers for brands and retailers. As the bench trial before U.S. District Judge William Orrick III entered its third week, Bazaarvoice expert Jason Goldberg, a veteran e-commerce consultant, offered a far different take on the market.