I'm not certain if a lot of the malware you see on the Jotti scanning service is likely to be encountered by the average computer user, but Clam has reached a detection rate of slightly over 40% (40.18% to be exact) there now. For comparison, Dr. Web, Kaspersky, and CP Secure all have a 40% rate also, and F-Secure has a 44% rate.

Regards,