rabbitoid:  avast! has intercepted and warned against a number (I'll say about a dozen over the years) of trojans and other threats against my system.  In some cases that's involved particular files being quarantined, or strong recommendations to immediately disconnect from particular web sites.  I'm afraid I can't PROVE to you that these threats really existed, but I take these warnings at face value.

If necessary, I could probably dig up a log for you.  I'm pretty sure the software keeps some kind of record of such incidents.