What is a hipster?

Lately, I seen some fashion blogs and magazines talk about "hipsters" and the young adults who were asked about whether or not they themselves were hipsters seemed like there was no way they wanted to be associated with this description. Until recently, I mostly associated hipness and hipsters with Jack Kerouac and other Beat writers. For those of you not familiar, Jack Kerouac is most famous for having written "On the Road," a novel about he and his friends taking car trips around the US in search of their identities and the meaning of life.

When they used the term hip, it was often used to describe African American jazz musicians, who they tended to idolize.

The word seems to mean something different to todays young adults. Anyone out there want to comment on this?