yeh it is for sure, but the reason its most popular is because people just use it due to it being part of Windows, and probably dont even know about other browsers, or if they do, dont want to change over to them as they are not used to the way they work (or cos they cant be arsed to switch)
people that are clued up use better browsers, and benefit greatly from them!
Also a hell of a lot of folk browse the net at work, and IE is usually the default browser, no others are allowed due to their it policy not allowing software to be installed, etc!