BlackBerry Messenger, or BBM, is a instant messaging application made specifically for BlackBerry devices. A BBM user can share instant messages with any other BlackBerry user, regardless of what cellular carrier they are using. Starting with BMM version 5.0, you can create groups in the application, which allow you to share a message or hold a conversation with multiple people at once. If you get tired of a particular BBM group, there is a menu command that allows you to exit it.
Press the “Menu” key, which has the BlackBerry logo on it, to launch the main BlackBerry application menu. Scroll to the “BlackBerry Messenger” icon and select it.