BEYONCE is like the EPITOME of CELEBRITY. I mean her CUBA HOLIDAYS only

her suprise album was on the news even outside USA
but RIHANNA has her strength too. Kids & Teens are behind her and they're interested in her music & life. + she had the chance to release her comeback album during the dawn of the digital era which propelled her to the digital queen level. Also it helped her youtube queen status.
But overall BEYONCE remains the un-touchable beloved mistress of the entertainment world. Look at the most tweeted events in history

she appears 3 times there (pregnancy anouncement, superbowl, surprise album)
I'm sorry, MADONNA sold better her albums but she was not loved that way. BEYONCE has just come and accomplished the things MADONNA missed (untouchable performer, beloved person, privacy....)