NetLOGO looks to be related to (or the evolution of) StarLOGO. Both are environments for exploring massively parallel, agent-based simulations in LOGO.
I especially like the HubNet feature; many users can participate in a simulation, playing the roles of agents in the system. The example they give is of students controlling traffic lights in a traffic simulation. It is up to each student to control one traffic light, but still participate in the optimization of the whole.
That, I think, has lots of cool opportunities for getting students communicating about the nature of distributed processes and programming. Very cool.