DOES NOT block the nastier popup windows, the whole reason you have a popup blocker...doh
Certainly NOT (Strict)

not working in any way i can see. (cant tell if its on or off.)

Doesn't work.

Doesn't work. I installed it, restarted Firefox, opened a web-page only to immediately get a pop-up ad.

As others have said, it doesn't work. Pretty poor for a Featured Extension.

does not work. has many problems

not working well with containers (often opens in non container tab, sometimes get option to open in specific container); unable to trust and open in background;

After installing weblinks didn't work on major websites like CNN and ESPN.

Youtube won't work with this addon. For so all, I tried to find what was wrong with youtube not loading, it's this addon!. Uninstall and you're good to go.

Removed add-on as unable to access YouTube(white blank page)even when disabled on browser!

its useless with openload videos nothing can beat its every-click-popups that means the technique that openload use it could any site use it as well so fix it quickly or you will get a ton of -1 rate!!

certainly can not block popups of openload.co

It doesn't appear anywhere in the UI.

doesn't block all popups, https://cup.aihedy.com/en-US/firefox/addon/simple-popup-blocker/?src=api is better

popups were blocked from the get-go for even links (javascript links that opens windows) i did not need blocked. I uninstalled the addon but the links are still not opening the popup window. Reinstalled my browser but lots of java links on different sites are not working anymore. Need to revert my browser back to before your addon. Im not really asking for help, Im sure i'll figure it out, I just hope this review helps to improve your product