You're choosing to completely ignore that it IS updated frequently, even monthly. Not only that, but updating a HOSTS file yourself is far more hassle than say, having a dedicated program do it for you. Which conveniently ignores the free ones. Nice, you brought up an invalid point and countered it all by yourself in brackets Every real ad blocker is system wide, you just have browser plugins stuck in your mind. An ad blocker isn't defined as a browser plugin, it's just a "reduced" form of one. Easy to say from someone who has no perspective of the code involved in the software itself. Maybe they do need to add it, or, for all we know it simply isn't that easy and adding every invalid IP address might be more effort/overhead than it's worth.