1. Rihanna Ties Janet Jackson For Second-Most Dance/Club Play Songs No. 1s

    December 03, 2012 4:15 PM EST With 'Diamonds' topping the tally, Rihanna and Jackson trail only Madonna for the most No. 1s in the chart's 36-year history. With the rise of Rihanna 's "Diamonds" to No. 1 on Billboard's Dance/Club Play Songs chart, the diva scores her sparkling 19th…