Trailrunner7 writes "Last year saw a monstrous increase in the volume of malicious spam, according to a new report (PDF). In the second half of 2009, the number of spam messages sent per day skyrocketed from 600 million to three billion, according to new research. For some time now, spam has been accounting for 90 or more percent of all email messages. But the volume of spam had been relatively steady in the last couple of years. Now, the emergence of several large-scale botnets, including Zeus and Koobface, has led to an enormous spike in the volume of spam."