The U.S. government shut down file-sharing site Megaupload on Thursday
Megaupload let users upload files with a single click
The government says the site's owners knowingly allowed copyright infringement
On Friday, pirated material was still easy to find on other sites
Megaupload, the file-sharing website shut down Thursday by the U.S. federal government, is a Web hosting tool that now finds itself accused of being an online haven for digital pirates.