I would say largely, the practical applicability of informal organization in anarchist practice. They are hostile to efforts of formal organizations such as unions, parties and federations managing their struggle and coordinate struggles through the utilization of horizontal networks based on affinity. Sure, the contextual difference between Greece and North America should be kept in mind but really, I doubt these differences actually legitimize some need for such organizational forms. Somewhat related (for example, in helping to establish affinity in order to expand and strengthen networks) is their extremely common use of general assemblies which I think North American anarchists should take note of and act accordingly.
