Elon Musk and Mark Zuckerberg have been engaging in a public feud on social media. The feud began when a Twitter user noted Zuckerberg's lack of activity on Threads, Meta Platforms Inc.'s new social media platform. Musk responded with a jab at Zuckerberg, suggesting he doesn't care about his new product. Threads initially gained 100 million users within five days of its launch, but reports indicate a decline in daily active users and app usage time.