What are the advantages of using Websphere message broker ?

WebSphere message broker provides services, based on message brokers to allow you to
Route a message to several destinations, using rules that act on the contents of one or more of the fields in the message or message header.

Transform a message, so that applications using different formats can exchange messages in their own formats.

• Store a message, or part of a message, in a database.
• Retrieve a message, or part of a message, from a database.
• Modify the contents of a message; for example,by adding data extracted from a database

What is the difference between Message Broker and Message Queue ?

WebSphere Message Queue facilitates communication between applications by sending and receiving message data via messaging queues. WebSphere Message Queue  provides a secure and reliable layer of transport for moving data unchanged in the form of messages between applications but it is not aware of the content of the messages.

WebSphere Message Broker is built to extend WebSphere Message Queue  and it is capable of understanding the content of each message that it moves through the Broker. Message Broker can do the following:

Matches and routes communications between services
Converts between different transport protocols
Transforms message formats between requester and service
Identifies and distributes business events from disparate sources.

Why do we require message broker when we have MQ ?

Both message broker and message queue works as middle-ware programs, that is to help communicating different systems, but message queue has a slight drawback that it cannot transform the messages. It can just send the message to other system.

What exactly do you understand by message broker ?

A Message Broker is an intermediary program that helps communicating multiple system to each other by transforming, routing the messages in the way they need.