Worldwide album sales. #KatyPerry : #TeenageDream sold 239k in it's first week worldwide. Second week sold 226k copies. #PRISM has done much better, selling 453k in it's first week worldwide. Katy is a few thousand #PRISM sales away from selling 1 million copies worldwide as well. She will get there next week no doubt! Great work! I'm liking the album more now than I did when I first heard it! #LadyGaga : #BornThisWay sold around 1.9 million copies in it's first week worldwide. Second week sold 487k copies. #ARTPOP has not done as well as that, selling 611k in it's first week worldwide. But now thanks to another strong week in Gaga album sales, ARTPOP has officially sold over 1 million copies worldwide. Album numbers have stayed pretty steady for ARTPOP, selling less than 50k less in it's second week. ARTPOP is definitely not an album for everyone, that much is true. But it is still a great album none the less. Has 'ARTPOP' done as good as 'Born This Way', no. But I think it will go on and sell at least the same amount as 'Born This Way'. Has 'PRISM' done better than 'Teenage Dream', yes. And it will also sell around the same amount as 'Teenage Dream'. Gaga and Katy do not need to have huge numbers, they needs to have steady numbers. That is what guarantees an albums longevity on the charts and with sales. They should ask #Adele for some tips on that!