Browser add-ons play a huge role in shaping the user experience, letting people customize their browsers by adding (or removing) features to fit their needs. Firefox, one of the most popular (open-source) browsers, provides public statistics on various aspects of its usage, including which add-ons are the most popular.
One particularly interesting trend is the overwhelming preference for ad blockers. In fact, the top 10 most-used Firefox add-ons are almost entirely dominated by them—which might be surprising to some but totally expected to many. This is how things look at the moment.

As the stats show, uBlock Origin, primarily used to block ads, trackers, and malicious websites, is the most popular add-on, making up 8% of all Firefox add-on usage. In the top 10, we also see two other familiar names—AdBlocker Ultimate and Adblock Plus—both offering similar features.
Privacy Badger, as the name suggest – a privacy-focused add-on that automatically detects and blocks third-party trackers, is also among the top preferred and installed Firefox add-ons. The only exception in this category is Video DownloadHelper, currently ranked third, which lets users easily download videos from the web to their computers.
It’s pretty obvious—users want to browse the web without annoying, intrusive ads getting in the way. But, like most things, there’s another side to the story.
For many publishers, ads aren’t just an extra feature; they’re the primary (and sometimes only) way to make money from their content. Those ads help cover website maintenance costs and, in many cases, put food on the table. It’s a delicate, multi-layered topic—but that’s a conversation for another time.
Now, back to the point. Firefox, being an open-source browser, naturally attracts users who care deeply about data privacy and internet freedom (though Mozilla’s recent moves have cast some doubt on this). So, it’s no surprise that privacy-focused add-ons are among the most popular. That said, you could also argue with a good deal of confidence that the same trend holds true for other major browsers.
In conclusion, it looks like the ongoing battle between advertisers—who are always looking for ways to profit from promoting products and services—and users, who just want clean, distraction-free content, isn’t going away anytime soon. As long as this struggle continues, quite expectedly, ad blockers will likely remain among the most popular browser add-ons.