[masklinn]

> Erlang doesn't seem to impose hierarchies at all.

True and not true, if you see Erlang as an object oriented language you still have three hierarchies at least:

1. for a given behavior, should it be packaged as a process or as a function? And if it's a function, in which module does it live? Granted, erlang's modules are "flat" so you don't get much of a hierarchy here.

2. Processes are organized in trees, because to send a message to a process you need a reference to it (its pid). Processes can be opted out of a tree by registering it globally, but that's about it. You could argue it's more of a bush as processes can communicate in a ring or with one another.

3. Supervision trees are most definitely hierarchies.