Cloward and Ohlin's basic idea is that in any society there are two main forms of opportunity structure.
1. Legitimate opportunity structures:
These are the various means a society develops to encourage people to achieve success (education, work, etc.).
2. Illegitimate opportunity structures:
These are the various illegal means to achieve success (crime, for example).
Thus, in any society people are socialised to value "success" (whatever that may actually mean in the cultural context of their society).
* Those who have the means to achieve success do so legitimately (they follow legitimate opportunity structures).
* Those who are denied legitimate means still desire success, so they pursue illegitimate means (illegitimate opportunity structures).
Thus, in any modern society, access to success through legitimate opportunity structures will be effectively blocked for many people and, in consequence, some turn to illegitimate opportunity structures (although, as in the legitimate job market, there is no guarantee they will find, in the illegitimate job market, the success they crave ).
Finally, in terms of youth subcultures, it is easy to see how young males, for example, who have failed in the education system - and have, therefore, relatively blocked opportunities for "success" in the legitimate job market - may develop subcultural groups (criminal / delinquent gangs, for example) as a means of organising illegitimate opportunity structures geared towards achieving culturally-defined forms of success.