Forget Microsoft. Google's biggest competition these days comes from the social media growth machine, Facebook. Google may have an "operating system for search" and a big bank of data about each of its users, but the future belongs to the masses of individuals -- and Facebook, the second-largest social network on the Web, knows comparatively more about each of its users. Google should be scared because facebook is growing at a stunning rate--it has nearly 30 million users now--with no signs of stopping. This, in part, is thanks to founder and CEO Michael Zuckerberg's bold decision to open up his social network to outside developers. AThat move ran counter to the prevailing ethic at rival MySpace, which has been scooping up application-development companies in an effort to stave off competition from third-party software developers on its site. More ...