Megaupload.com one of the world’s most popular file-sharing sites was shut down yesterday on charges that it illegally shared movies, TV shows, and e-books. A federal indictment accuses the company of costing copyright holders at least $500 million in lost revenue. In retaliation hacker groups went after several Web sites including those of the Justice Department and Universal. Ira Rothken is a lawyer for Megaupload.com.