Jacob Sartorius was once most famous for posting videos of himself lip syncing popular songs. On which media?

Explanation

The 8-year-old Jacob Sartorius fell in love with acting, diligently studying the craft and performing in Community Theater. In August 2014, Jacob uploaded his first video on Vine. In that video, he strongly spoke out against bullying. The year after his popularity on Vine started to grow as well as on the online video community musical.ly, where he respectively posted videos of himself joking and lip-syncing popular songs. This all led to amassing millions of followers on social media.