I recently delved into the use of ClamAV and in doing so I discovered that there are many third party definitions that give ClamAV the ability to filter SPAM (so not as a virus, just SPAM...) and that from ClamAV's responses it is It is also possible to understand which type of anti-spam rule has been activated.

It would be very nice if in the future SmarterMail provides an interface to handle this possibility in deep as real AntiSpam rules!