Most Active Botnet Families in 2Q10

Microsoft anti-malware products and utilities include detection signatures for many individual bot families, and the number continues to grow as malware creators pursue efforts to evade detection and create more effective botnets.

Microsoft desktop anti-malware products removed bots from 6.5 million computers around the world in 2Q10. The following link shows the top 25 Bot Families.
http://www.microsoft.com/security/sir/story/default.aspx#section_3_1