Websphere message broker also know as IBM Integration Bus which is IBM's integration broker from the WebSphere product family that allows business information to flow between disparate applications across multiple hardware and software platforms.

IBM Integration Bus/ Websphere message broker provides capabilities to build solutions needed to support diverse integration requirements through a set of connectors to a range of data sources, including packaged applications, files, mobile devices, messaging systems, and databases

Websphere message broker Features
Simplicity and productivity
Simplified process for installation : The process to deploy and configure IBM Integration Bus so that an integration developer can use the IBM Integration Toolkit to start creating applications is simplified and quicker to complete.
Tutorials Gallery : From the Tutorials Gallery you can download, deploy, and test sample integration solutions.
Shared libraries : Shared libraries are introduced in V10 to share resources between multiple applications. Libraries in previous versions of IBM Integration Bus are static libraries.
Removal of the WebSphere MQ prerequisite : WebSphere MQ is no longer a prerequisite for using IBM Integration Bus on distributed platforms, which means that you can develop and deploy applications independently of WebSphere MQ.
Universal and independent
Graphical data mapping
Industry-specific and relevant
Dynamic and intelligent
High-performing and scalable