Grum was the world's third largest spam botnet spanning over 100,000 computers and responsible for sending out approximately 18 billion spam messages everyday. To put that in perspective, Grum accounted for 18 percent of the world's spam messages.
The spam botnet has been taken down by the concerted efforts of security firm FireEye as well as cooperation from other parties. Earlier this week Grum's servers in the Netherlands and Panama were taken out. And now six servers in Russia and Ukraine have also been put offline, effectively eradicating the spam botnet.
Hopefully this means we will all be getting fewer mails trying to sell us fake Rolex watches and other useless products.