title: What is ActiveMQ used for - can we apply messaging concept using a Database?
body: <p>I looked it up and it used to send messages between 2 systems.<br>
  But why? Why wouldn't you just use a <code>Database</code>?<br>
  There must be some feature that <code>ActiveMQ</code> has that <code>Databases</code> do not?</p>