With these filters enabled, it can block specific requests from websites, usually the requests to serve an ad. Out of the box, Adblock Plus comes without any filters, but, it will offer you to add a filter subscription on first start. In order to block ads, Adblock Plus requires the so-called filters to 'tell' it which requests to block. Its primary purpose is to remove all intrusive advertisements from your browsing experience: YouTube video ads, Facebook ads, banners, pop-ups, pop-unders, background ads etc. What if Adblock Plus doesn't block an advertisement?Īdblock Plus is the most popular browser extension available for Mozilla Firefox, Google Chrome, Opera and Android.Disabling/Reenabling Adblock Plus on all Websites.Disabling Adblock Plus on frequently used sites.