With this in mind, it’s easy to see how your computer could start to choke in a flash. Multiply that by the number of ads that exist on your average Web page these days, and then factor in the number of browser tabs people usually have open.
An iframe is an HTML document that allows multiple documents from different sources to appear on the same website that’s how you can have one ad for Huggies, and another ad for Six Flags on the same page. According to Nicholas Nethercote, a developer for Mozilla, AdBlock Plus blocks ads by swapping each iframe on whatever website you’re using with another (roughly) 4MB document in order to keep that ad from appearing. Though add-ons like AdBlock Plus prevent a lot of ads from popping up, because of the way it goes about blocking those ads, your computer might be using more resources than it would be if you were to turn the add-on off. The reason why ad blocking browser add-ons and extensions are so popular, aside from the fact that people generally don’t want to see ads, is that fewer ads means there are more system resources for your Mac or PC to take advantage of, right? For AdBlock Plus, that may not exactly be the case, at least when it comes to using it with Firefox.