Facebook has a gun problem. In January the social media giant announced it was banning the sale of guns and ammunition on the site. The move was the culmination of months of behind-the-scenes lobbying from gun violence prevention advocates coupled with internal recognition at Facebook that the site is becoming a major e-commerce marketplace. But the ban isn't working. Sales continue to flood gun enthusiast groups around the country. While some have left the site... (GunPolicy.org)