Erlang isn't good for everything. Neither is Ruby. But together they create a powerful force that can be harnessed to engineer highly scalable systems that defer to Ruby for more mundane tasks. The secret to this unholy alliance is a two way communication layer called Erlectricity that lets you craft Ruby nodes that receive messages just like Erlang processes.
I will demonstrate how this setup can lead to elegant and extensible system design with simple examples, and then explain how Erlectricity helped us build a self-assembling, YAWS based meta-server called Fuzed that lets you put Rails apps or other Ruby servers into a heterogenous cloud.