The "Animal" era was far more sucessful than the "Rated R" era , Ke$ha had way more radio play and downloads than Rihanna did .
And I think your forgeting , Ke$ha , a debut artist sold 5 million copies, Rihanna is on her 5th album is yet to reach this feat .
Ke$ha is a digital monster :
example - Blah Blah Blah, spent what, 3 weeks on radio ? (
) yet is about to pass the 2 million mark. Both YLIMD and TIO plummeted quickly after they peaked on radio but continued to sell well . With just 4 singles she's sold 11 Million, no to mention the 3OH!3 song she helped sell