A Mac botnet?

Ars Technica has an article up about a detected botnet based on Mac OSX machines. This is interesting stuff since you don't SEE this kind of thing all that often. OSX is the #2 operating system after Windows, but it is a distant #2. Also interestingly the infection vector appears to be pirated software, a vector that bring a tear of nostalgia to my eye for its sheer antiquity. Clearly this would be a slow growing botnet, but that's OK since a large percentage of Mac users don't bother with AV software since they're not running Windows and "don't need it".

What would be more impressive would be a drive-by downloader ala IE, but with Safari instead. I don't remember hearing any press about anything other than proof-of-concept with that, though.