Location-based social networking game Foursquare has had a great year. They've got 1.8 million users, adding about 10,000 more every day. They've secured partnerships with tons of private companies , including Starbucks, Zagat, Bravo, and the New York Times Company, and have so far fought off rivals like Gowalla and Loopt.
Perhaps that's why Silicon Valley veterans Andreessen Horowitz (Marc Andreessen is a co-founder of Netscape) decided to become major investors. Along with Foursquare's existing benefactors like O'Reilly and Union Square Ventures, Andreessen Horowitz scrounged up $20 million  in funding for Foursquare, just as predicted . Says Ben Horowitz, the other half of Andreessen Horowitz (duh):
"There are already over 200 million smartphones out there and growing fast,” he said. “We’d like to see them build out the company to capture that opportunity."
Foursquare has apparently decided not to sell to another company (there've been rumors  involving both Facebook  and Yahoo) to focus on their own business. That $20 million will mostly go toward infrastructure, including the hiring of new employees and moving the company's office space to a New York City headquarters.