Types

These "types" should be considered as theoretical ideals, in the sense that subcultures do not necessarily belong to one type as opposed to the other type (they may, for example, be a mixture of types). 

As with most typologies (that is, classification systems) their main use is as a means of helping us (as students) get to grips with social phenomena that are frequently difficult to comprehend. That is, by broadly classifying a wide range of diverse subcultural groups on the basis of the general, perhaps essential, features they have in common we can impose a sense of order that helps us to understand their basic nature.

You should, of course, keep in mind that this "sense of order" is something we have imposed for the sake of conceptual and theoretical clarity (that is, to help us as academic students understand something about subcultural groups). Simply because we, as sociologists classify phenomena in particular ways does not, of course, mean that such a classification will be accepted by the people involved...