Rihanna Continues to Own Social 50, Lady Gaga Jumps to No. 2

Rihanna continues to reign supreme on Billboard's Social 50 chart this week. She holds at No. 1 on the tally, reeling from media excitement generated by her film debut in "Battleship." Further, a series of remixes of her popular single "Where Have You Been" hit iTunes last week.

The Social 50 chart ranks the most popular artists on YouTube, Vevo, Facebook, Twitter, MySpace, using a formula