Economy 7 August 2012 GIF of the day: Skynet is in your stock exchanges, taking your money High frequency trading has experienced a boom in the last five years. What next? Print HTML Reuters' finance blogger Felix Salmon presents the above animated gif, which shows the quantity of high frequency trades happening throughout the day in 14 American stock exchanges, charted between 2007 and 2012. Watch to the end, to see the enormous spike in activity in 2011, particularly following the US downgrade in August that year, then read Felix's analysis: Back in 2007, I wasn’t a fan of a financial-transactions tax; today, I am. And this chart shows better than anything why my opinion has changed. The stock market is clearly more dangerous than it was in 2007, with much greater tail risk; meanwhile, in return for facing that danger, society as a whole has received precious little utility. › Tale of a city: From hell to hipsville Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter. Subscribe More Related articles George Osborne's mistakes are coming back to haunt him The changing world of work Is Kezia Dugdale's tax rise the beginning of an honest debate about tax?