Drive-by download attacks menace UK.gov / The Register, 23 July 2008
http://www.theregister.co.uk/2008/07/23/drive_by_download_asprox_menace/
"Malicious downloads from compromised websites have replaced infected email attachment as the favourite tactic for malware authors. During the first half of 2008, web security firm Sophos detected 16,173 malicious webpages every day – or one every five seconds. The rate at which infected websites spring up is three times faster than during 2007."