McLEAN, Va. – One of the world's most popular file-sharing sites was shuttered Thursday, and its founder and several company officials were accused of facilitating millions of illegal downloads of films, music and other content.

January 19, 2012 One day after many popular websites went dark to protest the Stop Online Piracy Act (SOPA), and the same day as a major U.S. raid on filesharing website Megaupload, various Twitter accounts claiming to represent the "hacktivist" group Anonymous have taken credit for bringing down several websites, including UniversalMusic.com and Justice.gov - the site of the U.S. Department of Justice - in an action they're calling #OPMEGAUPLOAD. At about 6:30 pm, Twitter user @AnonDaily tweeted "Take Down Any Website, Any Owner, in No Time Flat! #Anonymous". Another apparently Anonymous-related Twitter account, @YourAnonNews, Tweeted this at 7 pm: "Good thing it's National Popcorn Day, everyone grab some and sit tight. "The Internet Strikes Back" is showing all night long! #megaupload", and earlier brought SOPA into the conversation: "Let's just say, for #SOPA supporters their #SOPAblackout is today. #Anonymous." A DoJ spokesperson told CNN "we are having website problems, but we're not sure what it's from". An Anonymous operative named Barrett Brown reportedly told British website RT.com that the DoJ's site was pulled down "in retaliation for Megaupload". Another website that appears to be affected at press time is the Recording Industry Association of America. Today's crackdown on Megaupload included four arrests in New Zealand and at least 20 search warrants being served across the globe. Co-founders Kim Dotcom (formerly Kim Schmitz) and Mathias Ortmann were arrested in Auckland along with two other employees and charged under piracy laws. Gawker has a different take on the #OPMEGAUPLOAD situation - writer Adrian Chen states that by clicking on certain links distributed by Anonymous, internet users may be inadvertantly aiding the hackers' attacks. You can read his story here.