1. Katy Perry's 'Teenage Dream' has Fourth No. 1 on Mainstream Top 40 Chart

    April 18, 2011 1:12 PM EDT Katy Perry's "Teenage Dream" becomes just the third album in the 18-year history of Billboard's Mainstream Top 40 chart to yield a quartet of No. 1s, as "E.T.," featuring Kanye West, ascends 2-1. The song follows &quo ...