It appears that multiple botnets may have been impacted by the recent raid to stop Rustock which impacted over 1 million users.
Harning Botnet was also shutdown along with Rustock
QUOTE: Rustock is not the only botnet that has stopped operations. The Harnig botnet, also known as Piptea, also went offline at about the same time. On the very day that law enforcement authorities, with Microsoft’s help, were raiding Rustock’s command-and-control servers, the servers belonging to the Harnig botnet–also known as Piptea–stopped responding, according to Atif Mushtaq, a security research engineer at FireEye. Rustock used to be spread by Harnig, suggesting some kind of a relationship between the two botnets, Mustaq wrote on the company’s Malware Intelligence Lab March 22.