What's the difference between “green threads” and Erlang's processes?

Question

After reading about Erlang\'s lighweight processes I was pretty much sure that they were \"green threads\". Until I read that there are differences between green threads and

Answer 1

Green Threads can share data memory amongst themselves directly (although synchronization is required of course).

Erlang doesn't use "Green Threads" but rather something closer to "Green Processes": processes do not share data memory directly but do so by "copying" it (i.e. having independent copies of the source data).