I'm curious-- is this a fad, or are we looking at a staple of cycling culture?
In the late eighties/early nineties, we saw mtb go from "extreme" culture to mainstream to walmart.
It seemed (maybe; i was younger, so i only barely remember) like a trend, but i challenge you to walk down a city block today without seeing one in the street or locked up.

Track bikes (or at least fixed gear bikes) seem to be going the same route. In the nineties, they were unheard of by all other than track cyclists and messengers. As the years grew, and messenger culture became more mainstream, we started seeing them more and more. Documentaries like Red Light Go and Pedal as well as ArtSchoolFashionŽ helped progress the cultural icon even further, to the point where kids at regular liberal art colleges ride them on campus; being a part of today's bar/band/blah culture all but requires them; even kids from the suburbs work on them while listening to their ipods.
Chain bike shops stock them from the big three, and LBS all have their favorite flavor.

It seems like track bikes on the street are here to stay-- partly because they're fun, simple to use, light, and attractive; partly because they're still loosely associated with cool edgy culture (how many years before mtb was just another bike?); partly because they end up being way cheaper than a similar machine w/ gears.

I wonder, though, how this is going to affect our bikes tomorrow.
Mention 1970s _______ pista, and we all perk up just a bit. Even road cyclists will stop and listen. Will my Bob Jackson be seen as a great find in 20 years, or just another hand-built boom track bike (we're kinda in the middle of one, right?). Will fixed gear culture fade into the underground only to resurface again, or will we look back and struggle to remember when everyone didn't have one?

I'm excited to see what happens.