https://www.finextra.com/pressarticle/69427/teen-chat-app-kik-to-launch-digital-currency

Teen chat app Kik to launch digital currency

Kin will be created as an ERC20 token on the Ethereum blockchain and will be integrated into Kik as the primary transaction currency.

Kik Messenger had approximately 300 million registered users, and was used by approximately 40% of United States teenagers

https://en.wikipedia.org/wiki/Kik_Messenger