Influencer: Dr. Luke Gottwald, Music Producer

LOS ANGELES (AdAge.com) -- Whether it was the radio, YouTube or prime-time TV, there was no escaping Dr. Luke's music in 2010. The pop music ?ber-producer had a hand in four Billboard Hot 100 No. 1 singles this year (five if you count the "Glee" remake of Katy Perry's "Teenage Dream"), collectively notching over 18 weeks atop the chart, and 14 other hits over the past 12 months.