The impact of social media on society today is undeniable - sites such as Facebook, Twitter, Instagram and Linkedin have millions and even billions of users.  Nurse, an academic at Oxford's Department of Computer Science, considers the positive uses of social-media information, while also explaining the various security and privacy risks associated with having a digital footprint.  Shedding light on what social media is, as well as how it works, he will show how to understand what you are telling the world when you join in with social media, and how to recognise good information from bad, as a reader.