They showed "Your Win XP might be infected " ; When I was using Win 7 beta.
It is funny for us, but, really I think, not so techy person often clicks them.
The websites those with such ads also should be warned.
Anyone can check about " how safe is the website " from Norton's Safe web
website . There should be strict implementation about website security.
SSL certificates are costly, its nearly impossible to buy and bear the recurrent cost of such certificate for small websites, forums etc. There should be an free but effective alternative for these.
SevenForums is Safe (Obviously) according to Norton: