San Francisco-based Kongregate, which operates an online social gaming site and community, has been acquired by videogame retailer Gamestop. Financial terms of the acquisition were not disclosed. Gamestop said that Kongregate will become a wholly-owned subsidiary of the firm, and continue to maintain offices in San Francisco. Kongregate is venture backed by Greylock Partners, Bezos Expeditions, and angel investors led by Reid Hoffman. The firm was founded in 2007 by Jim Greer and Emily Greer. GameStop said the acquisition would strengthen its digital platform and to help it become the "gaming aggregator of choice." Kongregate has around 10 million monthly players who use the site.