The only thing that looks like "pop-ups" to me would be when the cursor passes over an underlined word -- and a little tag pops into being to lead me to some advertiser that has bought that word.
I do get a strange audio message once in a while - and haven't yet figured out which post-er, which site, it's linked to. The message is a girl's voice telling me that I've won a pair of iPods. That's all she says -- then stops talking.
As for viruses, I'll say it again -- no virus protection on my computer, and in six years I've had one issue with what may have been one. Ah, the pleasantries of running Apple.