or boyfriend: you already know they’re dating someone else from the romantic selfies. But, unlike in real life, Facebook has no hierarchy of friendships. A classmate from one project at university who you haven’t seen in 15 years, a friend-of-a-friend from a stag do or a colleague you’ve never actually spoken to in person – they are all Facebook friends in the same way as your closest mate or your spouse or your mum. It doesn’t necessarily mean we see them the same way. Professor Robin Dunbar is famous for his research that suggests a person can only have roughly 150 people as a social group. Facebook hasn’t changed that yet, he believes, but, in an interview with the New Yorker, Dunbar said he feared it was so easy simply to end friendships on Facebook that, eventually, there may no longer be any need to learn to get along. 2 We care less about privacy There’s a wise saying: if you’re not paying for it, you’re the product. Facebook embodies that philosophy and created an entire industry from it. The astonishing thing is that users know that and they willingly hand over that information. Pew Research Center found that most young people are more than willing to hand over their details. An overwhelming majority of 91% post a photo of themselves, 71% post the city or town where they live, up from 61%, more than half give email addresses and a fifth give