In the wake of this week’s arrest of Julian Assange, irate “hacktivists” have taken to attacking the websites of a number of businesses that have frozen or terminated Wikileaks accounts. This week, the websites of MasterCard and Visa have both gone down to denial of service attacks. The group that purports to be behind the attacks, “Operation Payback,” isn’t new: they’re a group of Anonymous users who have previously mobilized over The Pirate Bay, ACTA, and other perceived affronts to free speech on the internet. Here, their promotional video gives a little explanation of their background. See the video after the click.