And if you haven't seen it, here is some classic. “Erlang: the Movie”:

— http://www.youtube.com/watch?v=xrIjfIjssLE

And sequel “Erlang: the Movie II”:

— http://www.youtube.com/watch?v=rRbY3TMUcgQ

Don't think wtf. Just watch.

I have a mug etched with a picture from that movie (by way of Learn You Some Erlang For Great Good): https://twitter.com/silentbicycle/status/299278899886579712 :)

Clause order matters.

--

  -module(ping).
  -export([ping/2]).

  ping(N, Pid) ->
      Pid ! ping,
      receive
          pong ->
              ping(N-1, Pid)
      end;
  ping(0, _Pid) ->
      ok.

  erlc ping.erl
  ping.erl:10: Warning: this clause cannot match because a
  previous clause at line 4 always matches

Correct -- immediately after the video was posted to InfoQ I posted a comment there to clarify and correct that error:

http://www.infoq.com/presentations/Erlang-OTP-Behaviors#anch...

A note about Steve Vinoski, if you ever need a book on the CORBA protocol go straight to his Advanced CORBA Programming in C++, beautiful book.