ClickLook is good for you who want to view your internet files offline. It's easy click and look mechanism. So you don;t have to click file and open file again. Just click.
But not just that. ClickLook is good for you who has webmail account. ClickLook will open your mail on the side page. So you could browse your inbox conveniently.
This is how ClickLook looks when on online mode.
And this is how ClickLook looks when on offline mode.