topsite squable security hazard

I am a member of this topsite, where different sites interact, and the users from the different forums are allways checking out other sites in that topsite. It's cool because the higher up you go the more visitors you really do get. The only problem is, they bring these goofy little drama's with them sometimes. There is always someone talking about someone being there for this reason or that reason, and it's all so damn gay. But it seems that some of these trouble makers know how to do this .. thing, where they can make users get a pop-up on your board that has a virus in it. Someone said that had been happening on my site a week or two ago one morning. Does anyone know anything about that, and if there's a security patch for that? I am so getting out of that topsite, it's so troublesome. But on the other hand, it brings a lot of people.