When u come for chart success, why don't you take one of Katy biggest songs from 2009 and compare it to SL
Lets see:
California Gurls
#174 Saint Kitts and Nevis
E.T.
#58 Moldova
#173 Saint Kitts and Nevis
Part of Me
#156 Saint Kitts and Nevis
VS:
Single Ladies
#63 Finland
If u want to compare Roar to a song, it would have to be Drunk In Love since it was released around the same time. Here I would agree that Roar had more of an impact even though Drunk In Love was huge in the Urban Community.
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However, one cannot measure impact by sales. Single Ladies' impact goes far beyond Roar and basically any other Purry #1-Song.