Social media web snares 'criminals'
By Niall Firth Five jewel thieves are on the run and seeking refuge in five different cities around the world. You have just 12 hours to find them, without knowing their names or what they look like. All you do know is what each will be wearing: a coloured T-shirt printed with a logo and a secret code. Seems impossible, doesn’t it? Well, one team, led by Manuel Cebrian at the Massachusetts Institute of Technology, managed to solve the Tag Challenge – within the allotted time – by leveraging social media and crowdsourcing to scour the cities for the hidden fugitives, finding three suspects in Washington DC, Bratislava, Slovakia and New York City. This, of course, was the point of the exercise. The Tag Challenge was organised by the US State Department to see how social media could help federal agencies track real criminals. It was modelled on the Red Balloon challenge in 2009 – set up by the Defense Advanced Research Projects Agency (DARPA) – which Cebrian’s team also won. The team’s trick, in both cases, was to set up an incentive scheme that encouraged as many people as possible to get involved in hunting for the suspects. Of the $5000 reward, each participant who sent in an image of a suspect would receive $500. Participants were also encouraged to invite others to join the hunt – for every friend that sent in a photo of a suspect that they had referred, the participant received an additional $100. On top of that, the recruiters of the first 2000 volunteers were given $1 for each person they signed up. The team also built a smartphone app for the Android mobile operating system. It allowed people to view the list of suspects as they were released, and submit photos of them directly from their phones. Cebrian says that while some teams also turned to social media to solve the challenge, those who spread their message entirely on Twitter may have been perceived as spammers by other users, hindering its effectiveness. “We knew that if we won we would raise the bar significantly for rapid mobilisation through social media,” he says. “Our next step is to try to reconstruct exactly how we won, what happened on the day of the challenge, and to learn something about what makes social media work in such amazing ways.” However, of the five suspects, the two in London and Stockholm were never found (each suspect was only asked to play his/her role for 12 hours). “We don’t plan to pursue them any further, although we believe we could, given a bit more time,” adds one of the team’s leaders, Iyad Rahwan at the Masdar Institute of Science and Technology, United Arab Emirates. The success of Cebrian’s team was a consolation after last year’s defeat when they were beaten into sixth place in DARPA’s Shredder challenge. The winning team used computer-vision algorithms and human volunteers to piece together documents shredded into more than 10,000 pieces. More on these topics: