When Facebook announced its recent $5 billion IPO, many applauded the company’s mission to connect friends and make the world a more open place. Experts described Zuckerberg as “noble,” “grandiose,” and “downright inspirational.” Twitter CEO Dick Costolo recently presented his vision in similar terms: “To instantly connect people everywhere.” Indeed, the intuitive appeal of such social networking platforms is hard to overlook and partly explains their rapid growth. But alongside the dominance of these sites has come a disturbing new trend — that social networks are altering the fabric of friendships, turning you into a business, and your friends and followers into customers of your content.