It did a good job of stopping popups. But it also stopped good popups. Example...On a college page I wanted to see the description of the course and I could not open in a new window and the coldstop prevented me from seeing the description. I had to turn it off first. Guess you could turn it on and off. this is the first software I have tried, all probably do the same thing. Just be aware if you WANT to see a popup, you have to close it.