What is Situationist? Situationist is an iPhone app that makes your everyday life more thrilling and unpredictable. It alerts members to each other's proximity and gets them to interact in random "situations". These situations vary from the friendly "Hug me for 5 seconds exactly" or "Compliment me on my haircut", to the subversive eg "Help me rouse everyone around us into revolutionary fervour and storm the nearest TV station". Members simply upload their photo and pick the situations they want to happen to them from a shortlist, in the knowledge that they might then occur anywhere, and at any time.

Who is behind it? Benrik, artists and authors of the cult bestselling "Diary Will Change Your Life" series.

Will it not attract stalkers and other unsavoury types? Situationist is moderated. The situations are initially picked from a shortlist. People can suggest their own situations, but these are vetted. Photos are moderated to exclude Chatroulette-style exhibitionism. And finally you can of course report anything dodgy. However Situationist is not for the timorous: the whole point is to interact with complete strangers. And in fact it is a protest against the demonisation of strangers encouraged by the media. Fear not!

Why is it called Situationist? Short answer: it is inspired by the Situationist International, a radical movement that sought to transform everyday life and the world through experimental forms of behaviour. Long answer.