AdBlock Ultimate is a free extension that blocks annoying ads, disable tracking and blocking domains known to spread malware. AdBlock Ultimate itself has no functionality, because it doesn't block anything until you "command" it. Of course, our team is aware that no user has the same computing skills as others. That's why we have included a few extensive filters that offer decent protection against annoying, flashy ads, YouTube commercials. It allows you to switch back on ads for particular websites in case you know there are no intrusive and misleading advertising there.