Youth Culture

What is youth culture really? Is there really such a thing as youth culture? I have been thinking about this and have come to the conculsion that youth culture cannot be defined. I mean how would you really define such an phenomea? Youth are so different in every city and town and even within those places you have emos adn skaters, jocks and band geeks, is there really any real tie that holds all youth together? Is there anything that really defines "youth culture"? What do you think? Am I way off?