Don't look now, but Iggy Azalea's started a movement. Just the other day, the "Fancy" performer introduced the "Mo Bounce" challenge, a social media trend that sees people upload videos of themselves ...

These days, if you can couple a song with some sort of Internet challenge, you'll have a much better chance of that song becoming a hit. Just take a look at the success of Rae Sremmurd's "Black ...