Rihanna and Lady Gaga. They are huge just about everywhere. Next up would be Beyonce. She's huge internationally, too, but not as big as Rihanna and Gaga are at the moment. Britney used to be huge internationally, but now she just tries to sell off her name alone and it's obviously not going too well. And then Katy is somewhat successful internationally. I am only a little successful out of the U.S. but I will be expanding with my next album and snatching everyone's wigs.
By territory:
North America - Lady Gaga and Katy Perry are huge there. But Rihanna is a close third. Beyonce and Britney are also very successful there, too.
South America - Shakira, Britney, Beyonce, and Rihanna
Europe - Beyonce, Shakira, Rihanna, and Lady Gaga
Africa - Rihanna and Shakira
Asia - Avril Lavigne and Lady Gaga
Australia - Pretty much all of them.
But the largest are probably Rihanna and Gaga at the moment.
I took Adele out because she isn't a popstar, but she's huge in Australia, North America, and Europe right now.
