he BlackBerry Messenger SDK provides APIs that allow you to leverage the social features and functionality of the BBM platform in your application.
BBM is an instant messaging program designed to allow BlackBerry device users to communicate with each other. Since its introduction to the suite of core BlackBerry applications, BBM has quickly become one of the most widely used applications on BlackBerry smartphones. Users do not need to sign into or out of BBM. As long as their BlackBerry devices are connected to a wireless network, BBM can keep users connected to their BBM contacts and groups.
The BBM SDK, used in conjunction with the BlackBerry Java SDK, lets you use the same infrastructure upon which BBM is built to communicate between instances of your application on multiple BlackBerry devices. For example, in a chess game application, a BlackBerry device user could invite a BBM contact to play a game of chess, and the moves could be communicated back and forth using the BBM platform.
Leverage the features of the BBM platform
You can access the same infrastructure that BBM, one of the most successful and widely used mobile social platforms, is built upon. With the BBM SDK, you can develop applications that incorporate social features such as peer-to-peer connections between BlackBerry devices, or integrated chats. There is no need to develop these social features yourself, and no server-side development is required to support them.
The BBM platform provides support for the social aspects of your application, such as tracking which BlackBerry devices your application is installed on, managing the connections between instances of your application, and proactively discovering the contacts who have already installed the application.
Increase the stickiness of your application
A sticky application is one that users find useful, engaging, and use frequently. When you integrate BBM into your application you can create a community where BlackBerry device users can get together, socialize, and communicate. Adding this social aspect can help your application maintain its presence on BlackBerry devices and help attract users.
Increase the discoverability of your application
When people like something, they want to share it with others. Because BlackBerry device users can communicate with any or all of their BBM contacts from within an application, when you create a BBM connected application, you have a built-in advertising system.

Users can not only encourage their contacts to download your application, they can actively invite them to do so by sending an invitation that links directly to the application details page in the BlackBerry World storefront.