The concept of influencers is hardly a new one. Through newspapers columns and TV sports, we’ve long been accustomed to hearing informed opinion from, say, Martin Lewis on money, Nigella Lawson on food or Mark Kermode on cinema. How the digital revolution has changed the game, however, is by providing a plethora of platforms from which literally anyone can have their say.

Online, you will find hordes of people holding forth on a number of topics: gaming, beauty, travel, fashion, fitness… virtually anything you can think of. What qualifies them as ‘experts’, however? Is it safe for young people to consume the oceans of content they generate? This guide brings you the essential information on the influencer phenomenon.