ASPEN -- The most important battlefields in America’s war against Islamic State terrorists may be Twitter and Facebook, experts told a crowd at the Aspen Security Forum here Friday. “This arguably is the most complex challenge the federal government and industry faces,” said George Selim, who heads the Department of Homeland Security’s community partnerships program. Federal officials have warned for two years that social media sites have become tools for terror organizations that use them to recruit and radicalize followers. Facebook’s head of global policy Monica Bickert said her firm and other social media sites are working overtime to stamp out radical posts. Read more on Colorado Springs Gazette