Webroot released its quarterly report on spyware today, claiming spyware infection rates are at their highest since 2004.
During the second quarter of 2006, Webroot researchers found that 89 percent of consumer PCs were infected with an average of 30 pieces of spyware – a slight increase from the first quarter of 2006 when infection rates returned to alarmingly high levels after a supposed lull in spyware infections during the second half of 2005. According to the report, new distribution channels, advanced spyware technologies and a reliance on free anti–spyware programs are all contributing factors to the startling increase.
The report states that the number of malicious websites increased from last quarter reaching 527,136. Webroot claims the most prevalent trojan is Trojan–Downloader–Zlob with over a million traces detected. I don't know about Webroot's other statistics, but I do believe they are correct in saying Zlob is the most prevalent trojan. Zlob is typically responsible for downloading the rogue anti-spyware programs, like SpywareQuake, SpyFalcon, and so on. It seems like every week there is a new rogue anti-spyware program, typically downloaded by Zlob trojans. The most recent example I've seen, VirusRescue, has been written up here complete with screenshots.