Largest spam email botnet taken down

In March 2011, Microsoft and US federal law enforcement shut down the "Rustock botnet" – the largest generator of spam email in the world, at its peak responsible for sending out as many as 44 billion messages every day, more than 47% of all daily spam traffic. A botnet works by infecting PCs with malicious software (also known as "malware"). The malware enables the botnet to control the PCs remotely, forcing them to send out spam. Estimates suggest Rustock may have enslaved as many as 2.4 million PCs.