As young people flock to WhatsApp, LINE and other chat apps, Facebook struggles to stay relevant. In response, it's created better emoticons – called Stickers – that are part of a deeper shift towards pictures as a primary way to communicate.

The way teens create identity is changing. With more tools to express themselves, access to a world of information and subcultures that bloom and wither in a matter of days, affiliation to traditional tribes has become less important.

Since 2011, Dolls Kill’s candy-coloured rebellious clothing has proved a hit with the Tumblr set, with sales reaching $7.5 million in 2013. But how has this brand managed to sell ‘bad acid trip’-inspired miniskirts by the bucket-load without any traditional marketing?

Online platform Imgur is rapidly evolving from a simple image host to a huge and highly sociable user community – and brands are taking notice. But how will Imgurians respond to brands engaging with them on their own turf?

One in three teens claim they could make money by creating YouTube videos. The success of social media stars like Bethany Mota shows that celebrity endorsements aren't influential as they used to be. Today's teens want inspiration from cool kids who could easily be their mates.

PewDiePie is the most subscribed channel on YouTube, and its creator makes more than £2 million a year on ad sales. He's one of YouTube's elite – a new generation of hyper-influential media moguls. But why are 30 million teens watching a stranger play video games?

Can games change a player's interests and opinions? 'Persuasive gaming' designers believe they can, and have set their sights on encouraging proactive approaches to well-being and prosocial behaviour through the first ever master's degree course in persuasive gaming.

In a not-so-distant future, Aiden Pearce strolls the streets of Chicago. Pulling a smartphone from the pocket of his inconspicuous trench coat, he hacks the nearest ATM and steals someone else's cash. For those who know what they're doing, a connected city is just waiting to be exploited.