Peter Gutmann sent an email[REF] noting that the Storm botnet comprises between 1 and 10 million PCs depending on whose estimates you believe.
An article in PCWorld [REF] dated October 21, 2007 says that a network security analyst presented findings at the Toorcon hacker conference in San Diego on October 20, 2007, saying that Storm is down to about 20,000 active hosts or about one-tenth of its former size.