Bey wasn't a factor musically until the last two weeks of the year, but culturally Bey owned 2013. Everything she did was a monster event. The inauguration, the Super Bowl, the Cuba trip, the hair cut -- she stayed in the news. I have never seen such a level of ubiquity of an entertainment figure that really had nothing going on as far as new music/movies. It was pretty crazy.
I think musically, Katy but overall Bey and it's not close.
2009-2011- Gaga
2012- Adele
2013- katy got overshadowed by Beyonce
2014- Again katy gets overshadowed by Taylor.
2009 Gaga got overshadowed by BEP
2010: Gaga owned it
2011: Adele
2012: Adele
2013: Katy
2014: First half of Katy and second half Taylor so it's kind of equal but Katy takes the edge because of her tour and everything else of her global achievements!