How TikTok, the new "hit machine", chooses which songs go most viral

When Megan Thee Stallion took off her bright orange mask and walked onstage to accept her Grammy on March 14, she fought back tears and thanked God, her mother, and her managers for helping her become the first female rapper to win the award for best new artist in two decades. But the rapper, whose real name is Megan Pete, made no mention of another entity that helped turn her song Savage into a No. 1 hit: the mobile app TikTok.

TikTok, a social network where people post short videos, often set to music, has become this generation's hit machine. Like many