A former social-gaming developer just got some cash to fund its new strategy of acquiring older games and serving up ads in them.

RockYou, a mobile-game publisher that is focusing on building an in-game ad network, revealed today that it has secured a $10 million financing deal. FastPay, a lender that specializes in digital media, provided the capital. While RockYou was once a social-game developer, the company has shifted to building a network of players to serve ads to by acquiring aging social and mobile games from others. The company plans to use its new funds to pay for further acquisitions in an effort to bolster its appeal with marketers.

“Brands are realizing that gaming audiences are extraordinarily more engaged compared to practically all other mediums,” RockYou chief executive officer Lisa Marino said. “Today’s funding will help us continue to grow our premium game inventory, thereby giving brands an even more powerful way to reach the players that will be most receptive to their products.”

RockYou has acquired around a dozen apps and games from other companies over the last year. That has enabled it to grow its gamer network to 75 million players while not developing anything original. The publisher has more than doubled its revenue year-over-year, according to Marino.

“We’ve worked with RockYou over the last year on the financing of several strategic game acquisitions,” FastPay CEO Jed Simon said. “The growth potential for in-game advertising is enormous. RockYou’s growing video ad inventory puts it in a very unique position in the market and one that’s proving to be very attractive for large brands.”

RockYou’s strategy shows how free-to-play gaming has shifted the way the business works on social and mobile. The gamer is no longer the sole customer as marketers provide a significant chunk of the funding. That enables a company like RockYou to survive by going around and purchasing older games and serving up ads to their small but dedicated audiences.