Hehe, there's always been something that's "hip", and it's about the zeitgeist, and the counterculture. Someone makes a statement, it's understood by a few, and the rest start dressing up like them.
For instance, 50's Rockers wore leather jackets because they rode motorbikes. It's a safety feature. Because rockers were "cool", leather jackets became popular, even among people with no motorbike. The rave movement of the 90's shifted a lot of counterculture thought into the mainstream anyway. Fight Club, the Matrix, were all part of the normalisation of those things. 70's show, Weeds, all show a new modern teenager, a reason-aware teenager, internet, who smokes pot AND studies hard.
Which means that nowadays, our counterculture is actually mainstream. Being "hip" can no longer be associated with a dress-code, or a genre of music, or an individual drug. It's given the hipsters - those who like to "look" cool - nothing to be.
So they revel in individuality - not their own individuality, which is that which makes a society strong, but in the originality of past heroes, seeking obscure music and being retro just for the retro's sake.