Credit card giant American Express has spent $30 million to take control of Sometrics, a virtual currency company that works with social game providers including BigPoint, Nexon and OMGPOP. The Sometrics platform will be integrated into Amex Serve, the credit card company's recently launched, PayPal-like online and mobile payment system. This integration will eventually allow Serve users to "purchase virtual currency for hundreds of games," and participate in loyalty programs from various merchants, according to the Tuesday announcement. The move comes after PayPal announced last week that its technology would be used to power real-money transactions in Diablo III's auction house, building off the company's announcement of digital goods micropayment platform last October. American Express previously dipped its toes into the virtual currency market by allowing card users to redeem membership reward points for Zynga's in-game currency. Sometrics recently boasted that it has sold 3.3 trillion units of its Game Coins virtual currency since launching in 2007, with over 2 million users spending the currency every month on dozens of social games. The GameCoins site also boasts a meta-game of its own, with branded missions, raffles and other activities focused on engaging the community to earn more coins by sampling promoted games. Sometrics has received two rounds of venture funding: a $2 million round led by The Mail Room Fund in 2008 a and $4 million round led by Steamboat Ventures in 2009.