I want to make one thing clear -
TheCatSite.com has never served any pop-ups, never does and never will!!! I hate pop-ups as much as you and I would never ever have them on my site!!! The only pop-up window here is on the main page and it tells people about the newsletter. If you have cookies enabled, you will only see that one once every 3-4 months.
My thoughts as to where you may be getting the pop-ups from when you visit the site:
1. They may be coming from the site you came from. Many sites have what they call "exit pop-ups" so when you leave them and move on to another site you get a pop-up.
2. A more sinister option is one of the zoola type applications. They're a type of spyware that installs itself on your pc and then serves you ads. They're very nasty - they can actually see that you visit a certain site with banners and replace the banners on the site when you view them! It's really upsetting for webmasters - they are parasites living on someone else's traffic