potential malware or scam from ad server

so about 10 minutes ago I get one of those ads over the forum that pops over the screen and follows it down in the middle preventing me from reading anything for the most part. the ad said something about windows detecting internet explorer running in an unsafe mode and needing to install something and change settings... This is rather funny considering I'm on an old Power PC G4 Mac mini running firefox. Thought I'd bring it up before someone with the lesser OS falls for it.

if you got firefox, install Adblock +
wave bye bye to ads.

only happened that one time, never happened anywhere else