Mark Zuckerberg One of the first decisions Larry Page made after replacing Eric Schmidt as Google's CEO was to make social a top priority. Instead of being discouraged by its previously lackluster social efforts (like Google Buzz and Google Wave), the Mountain View-based company is working harder than ever to get itself into the social game, most recently with its new Google+. Google has every reason to be desperate. Among others, it must confront Facebook. With the data of 700 million users worldwide, the social network giant has the capacity to threaten some of Google's most important business with features like an ad network that knows the workplace, location features, users' interests, and games. How about a YouTube clone with an instant userbase of 700 million users, sharing videos right from their phones? Or a full-fledged webmail and calendar service? These aren't happening yet, but there's no guarantee Facebook won't expand its empire -- just like Google did in the past decade. For now, Facebook is settling for just being the top social networking site, sitting back and watching its valuation balloon by the billions -- enjoying a $70 billion valuation in the latest round of investments by GSV Capital. Meanwhile, Mark Zuckerberg's net worth rose to $18 billion, surpassing Google founders Page and Sergey Brin. The young Facebook founder is now ranked third in the richest tech titans list, just behind Oracle's Larry Ellison and Microsoft's Bill Gates. No wonder social is important. Source: Forbes Photo: Cyril Attias