Computer World had an article last week on the Kneber Botnet. According to the article, this Botnet has been attacking systems worldwide since late 2008. The Botnet has affected systems in up to 196 countries. The countries with the most compromised systems were the US, Egypt, Mexico, Saudi Arabia and Turkey.
The Botnet, a variant of Zeus, collects financial and login data. In one month the Botnet stole 68,000 corporate login credentials and online e-mail & social networking user accounts. And that was just from one month, the botnet was active for about 18 months. Read the full article at Computer World.