Let’s say you want to have a bulletin board of some kind. You want to allow only some people to see it, by subscribing to the bulleting board.
This can be done using the publisher/subscriber model of ZeroMQ.
Now, let’s say you need to send some asynchronous messages. That is, when a message is sent from system A and needs to get to system B, it is guaranteed to be delivered later, even if systems A and B cannot communicate at the moment when that message is sent. You can imagine a use case being SMS messages.
This can be done using asynchronous messaging model of ZeroMQ.
Basically, any JMS compliant solution like ZeroMQ will allow you to reliably broadcast or send a “message”, whatever that message may be, to some other party with as little hassle as possible.