I'm getting a lot of supposedly legit anti-spy junk on my relatively new (2 months old) Imac. It says it has noticed a lot of porn sites placing cookies on my set. The only site not 100% free I go to might be Limewire. However, I thought Apple was immune to this type of garbage. Today's message even had the Firefox symbol to lend authenticity. Also, I'm getting a lot of back door adds and messaging when I leave a site. Any suggestions as to anti-spy or anti-cookie stuff that will work with an Apple Imac?