title: Difference between ask and tell in Akka?
body: <p>Reading the Scala doc I am having difficulty understanding the difference between ask and tell.</p>
  
  <p><a href="http://doc.akka.io/docs/akka/snapshot/scala/actors.html">http://doc.akka.io/docs/akka/snapshot/scala/actors.html</a> states :</p>
  
  <blockquote>
    <p>! means “fire-and-forget”, e.g. send a message asynchronously and
    return immediately. Also known as tell.</p>
    
    <p>? sends a message asynchronously and returns a Future representing a
    possible reply. Also known as ask.</p>
  </blockquote>
  
  <p>If the actor I'm using spawns a web request then what is the difference between ask and tell ? In both cases the request will be spawned asynchronously and must wait for a response, in other words how can "tell" return immediately if the actor is invoking a web service and awaiting a response ?</p>