In the early to mid-2010s, before smartphones became universal, a specific file type—the .jar —was the lifeblood of mobile social networking. For millions of users on Nokia, Samsung, and Sony Ericsson feature phones, the "Wap Facebook Chat.jar" application was the primary bridge to the digital world. What Was "Facebook Chat.jar"?

Even on low-spec cameras, the app allowed users to share photos directly from their phone's gallery to their wall.

The core appeal was the ability to send and receive messages without refreshing a WAP page.

The .jar file acted as the user interface on the phone.