30000 Internet-connected zombie networks in 2004

Richard Clarke, former security advisor to the President of the United States, estimated the number of zombie computer networks at 30,000. This is a surge from 2,000 networks observed last year. The numbers are not exactly informative, as it doesn't tell about the total number of Internet-connected PCs infected with trojan horses and viruses, but former security advisor and current chairman of Good Harbor Consulting estimated each network to have a thousand of bots.