title: Efficacy of peer monitoring in Akka
body: <p>I am trying to wrap my brain around Akka and after reading the 2.3.11 dev guide am still a bit confused about Actor monitoring. I essentially have two main concerns:</p>
  
  <ul>
  <li>The messaging that occurs when a watched actors dies or is restarted; and</li>
  <li>The necessity or usefulness of "<em>peer monitoring</em>" in the first place</li>
  </ul>
  
  <p>When I <code>context.watch(someActorRef)</code>, I am confused about the messaging I receive when <code>someActorRef</code> dies or is restarted. Do I get a <code>Terminated</code> message or a <code>DeathPactException</code>?</p>
  
  <p>To me, monitoring is really a form of supervision, and so it only makes sense for a supervisor/parent actor to <code>watch</code> a child actor, however I believe the API takes care of this supervision automagically under the hood via supervisor strategy. So it seems like <code>watch</code>/<code>unwatch</code> are there for non-supervisor actors to...well...supervise other actors that aren't their children. So I'm concerned about <em>why</em> I would want to use these API facilities in the first place, to monitor what is essentially another "peer actor".</p>