This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
In particular, Erlang is fantastic for gluing other systems together (in particular if they speak strange protocols), or controlling and supervising, distributing traffic, etc. But it can be used for a wide variety of tasks (as Wings3D has shown).