Federated clouds are like chupacabras– the mythical goat vampires of the Southwest — people think they have really seen them, but everyone has a slightly different vision of what one looks like. In a panel Tuesday at Structure:Europe, GigaOM’s Barb Darrow led Ditlev Bredahl, CEO of OnApp; Mark Cravotta, SVP Worldwide Sales at Tier 3; David Drai, Chief Strategist Emerging Products Business Unit at Akamai; and Pascale Vicat-Blanc – CEO of Lyatiss in a lively discussion that covered Amazon, the future of service provider clouds and how Europeans don’t like to buy cloud computing, but are fine with purchasing on-demand virtualized servers. Check out the video below for more.