I just re-listened to the episode yesterday and now I really want to listen to Ross run his game of Night's Black Agents set in Tokyo.
I'm going to pick up a copy of the book Ross mentioned concerning the different social groups in Japanese youth because that aspect of Japanese society really interests me, but I wanted to say a little something as I've lived in Japan for a while and know a little about how young people behave over there.
While many people think of Japan as having these crazy sub-cultures (and they do) over the past 10 years Japan has begun to shift the way their employment of young people into the workforce from long-term employment with full benefits - a.k.a. the traditional concept of the salaryman - to the more westernised concept of casual employment. This has led to a change in the way young Japanese people view joining the workforce and how they act in their own social groups. These social groups, which were once a method for young people to rebel against the traditional institution of life-long employment within a single organisation have become less rebellious to some extent, and are now more like a coping mechanism for dealing with the realization that they may never get to have one of these safe jobs.
There is much more to it than that of course, but the general feel I got from these different social groups when I was over there was young people joined them much like any other westerner would join a club or sporting team in order to meet new people and have fun, the notion that these fringe groups where is some way 'sticking it to the man' was not really supported by any of the people I met over there.
I hope this helps. If there is anything else you think I might be able to help with I'd be more than happy to answer questions. just for clarification, I spent 4 months studying in a Japanese town a couple of hours away from Tokyo so my experiences with these fringe groups is pretty diluted but i met a few people who were part of these groups.