Here's how Anonymous has shut down Web sites ranging from the U.S. Department of Justice to the Recording Industry of America using tactics that go by the acronyms DDoS and LOIC.

The hacktivist collective has targeted and taken down sites for a wide number of reasons, the most recent, Thursday, being the federal government's decision to go after the popular file-sharing site Megaupload, indicting seven people connected to the site on a range of piracy-related charges.

The Thursday attacks by Anonymous totally crippled the Web sites of the U.S. Department of Justice, Recording Industry Association of America, Universal Music, Motion Picture Association of America, U.S. Copyright Office and others.

Twitter users associated with the collective claimed Thursday that more than 5,000 people worked together to target the sites using a hacker application that facilitates what are known as distributed denial of service (DDoS) attacks, calling it the collective's largest such effort to date.

DDoS has long been one of the biggest guns in the Anonymous arsenal. When enough people participate in a DDoS attack on a specific site, it can shut it down by overloading the servers that host it. There are other guns - like doxing, which involves dumping incriminating or personal information about targets onto the Internet - but DDoS is the one that causes their largest coups, such as Thursday's coordinated site takedowns.

To participate in a DDoS attack, a hacker must download LOIC (low orbit ion cannon), which is an application 4Chan hackers created to facilitate massive DDoS attacks. The user then just puts in the URL or IP address of whatever site he or she wants to attack. If enough people participate in the DDoS effort, it simply floods the target site's servers with purposeless requests, thereby causing the server to go down.

And that's it - these few easy steps are all Anonymous has to follow to shut down Web sites.