Boasts about sexual conquests on a now-deleted Web page could trigger felony charges against a popular Rogers High School student athlete and others, the latest twist in a swirl of accusations, comments and protest involving social media.The furor in the Elk River Area School District on Tuesday transcended the dispute over a controversial tweet by the student and exposed the sexually explicit and often vicious exchanges that fill popular online pages created by students at many Minnesota schools. The anonymous posts include bragging messages, accusations and insults directed at students, teachers and others.Rogers Police Chief Jeff Beahen said the “Rogers...