If you actually LISTEN to the words of the song (I.E. the VERSES), you'd know that the song is about (guess what) their EGOES. Jay-Z being the best rapper alive and Beyonce being the best pop sensation right now (and they act like this cuz they can back it up). Fame, popularity, respect, swagga and talent: they've got it all. As a result, they both have a big ego.