I have tried various Anti Virus tools for the Mac and all of them are absolutely crap. Most of them only catch Windows based threats, so if you have a Mac and Windows you can use the Anti Virus to make sure you are not going to accidently forward them an email with a MS Word file with a virus in it, but that is all it is good for.
Also, notice Apple removed the knowledge base article, mainly because it was inaccurate and the wording was extremely poor. Now you may find this weird, but there is plenty of Anti Virus programs for Linux too!
