Well we all know that katy perrys E.T will only be there for a a few days at N.1 or at least 1 week so dont get to exited just yet. lady gaga its bigger world wide and katy is know in may countries but not all of the world. and finally Lady gaga is the most popular artist in this whole planet but lets include her sales and so on. shes bigger than Madonna and Maichael Jackson and i think it will stay that way in many years.