Social media is fuelling our human urge to share, affecting the information we depend on to make smart decisions, from choosing politicians to doing business to raising money for charity. Tell Everyone delves into contemporary culture to reveal how social media has become the planet's nervous system--amplifying the power of individuals, informing our choices and shaping how we learn about our world. Writing with journalistic flair but with academic rigour, online news pioneer and social media maven Alfred Hermida lays bare why we feel compelled to share news, gossip and information, and always have. Every day more than 500 million messages are sent on Twitter, 800 million people share four billion stories, links, photographs and videos on Facebook. Every minute, 100 hours of video is uploaded to YouTube. And the flow is ever-increasing. In this new era of media saturation, what do we mean by "the news"? Is "the most trusted name in news" today a veteran anchor on television or an undergraduate tweeting from Tahrir Square in Cairo? Tell Everyone spells out how our ability to create and share news is shaping the information we receive and depend on to make informed decisions, from choosing politicians to doing business. Drawing on historical examples, real-world experiences and leading research, Tell Everyone explains how the power of sharing is transforming how we understand and give meaning to world events.