Damus was removed from the App Store because it violated Apple's App Store Guidelines by allowing users to send "tips" (zaps) associated with receiving content from digital content creators through a mechanism other than in-app purchase.

Apple's App Store Guidelines state that apps that allow users to purchase digital goods or services must use Apple's in-app purchase system. This system allows Apple to collect a 30% commission on all in-app purchases.

Damus' zap feature allowed users to send Bitcoin to each other directly, bypassing Apple's in-app purchase system. This meant that Apple was not able to collect a commission on the zap transactions.

Apple gave Damus a 14-day deadline to remove the zap feature from its app. Damus did not comply with this deadline, and the app was removed from the App Store on June 26, 2023.

The removal of Damus from the App Store has raised concerns about the future of apps that allow peer-to-peer transactions. Apple's in-app purchase system has been criticized for being anti-competitive, and the removal of Damus suggests that Apple is not willing to allow apps that bypass its system.

It remains to be seen whether Damus will be able to find a way to comply with Apple's guidelines and return to the App Store. If not, the app's removal will be a setback for the development of decentralized social networking apps.