[JustSomeNobody]

I get that this is probably written for people familiar with Erlang, but a quick suggestion if I may:

In the Behaviors section you talk about behaviors being similar to interfaces in Go and give a Go example. But then you switch examples for Erlang. Maybe show the Joe/Mike example written in Erlang and then say, here's a more complicated example (the key-value example) that really describes behaviors better.