"Business used to be done with a handshake. Sometimes, it still is. But for a growing number of potential customers, the majority of research, referrals, and recommendations are being done by virtual rather than physical word, via social networks like LinkedIn, Facebook, and MySpace.LinkedIn, a social network for business professionals, attracts nearly 69 million monthly unique visitors, according to Web analytics firm Compete Inc. Facebook, one of the largest general-interest social Web communities in the world, has more than 200 million active users (as of April 2009). More than half of that number log onto the network every day, sharing more than a billion pieces of content each week, according to Facebook research findings. Blogs, in which readers can respond to content posted by blog authors, numbered more than 112 million in 2008, states Web research firm Technorati. And 33 percent of U.S. Internet users say they read them..."