5.28pm:�More high-tech details on how Operation Payback is managing to create chaos some of the world's biggest e-commerce websites, thanks to�Netcraft anaysis:

Operation Payback is announcing targets via its website, Twitter stream and Internet Relay Chat (IRC) channels. To muster the necessary volume of traffic to take sites offline, they are inviting people to take part in a 'voluntary' botnet by installing a tool called LOIC (Low Orbit Ion Cannon � a fictional weapon of mass destruction popularised by computer games such as Command & Conquer).

The LOIC tool connects to an IRC server and joins an invite-only 'hive' channel, where it can be updated with the current attack target. This allows Operation Payback to automatically reconfigure the entire botnet to switch to a different target at any time.