This one is great, thank you. But how do you know that you have to use "#div(id*=pop)"?
You should analyze the page HTML code using DOM Inspector (if you know enough CSS coding) or saving the page to local archive and checking it using an HTML editor like NVU (if you are a dumb like me).
Checking the code you can see that the popup window is a DIV element with a property: id=pop_44c91dc1e5ffc. I did not use the full id just in case they change it when updating the ad, but only the "pop" part.
It is not very easy, but learning a bit of HTML it takes only a short time and can be very amusing, and you can avoid a lot of very disturbing popup-ads.
Note: it is possible to make filters hiding every element and ad of the page and subpages using CSS rules and element hiding, but only real experts (and we have a lot of them in this forum) can do it.