I think advantage of IE is the loading time, it seems loading fast.
All other things like - security, tabs, popup blocker etc, IE copied from other browsers isn't it ?
So naturally, with the speed as advantage its gaining popularity.
I Was using Mozilla for a long time, and now FF. Pretty happy with that and use IE only when my clients ask me to chk sites etc in IE.
And pirated Win users can go for IE7 now, so sure it will be the first in India and Asia !! It might be a trick by MS too, like if they block all pirated users from using IE, they will go for other browsers - quite naturally