The word avant-garde, so much used in connection with the various manifestations of contemporary art, is starting to have a strange, ironic ring to it. One might even claim that it is starting to signify what is behind the times, rather than in front of them.
Like all such terms, it is in fact a metaphor, rather than a direct description. Borrowed from old-fashioned military terminology, it seeks to describe a situation where social norms are being perpetually challenged by artists. In the military sphere, where it originated, it is long out of use. Armies no longer marshal themselves in regular formations of the battlefield. There is now no recognized grammar of warfare - any more than (come to think of it) there is a recognized grammar of art. The mantra now is: "It’s art because I say it’s art!" In these circumstances, it is increasingly difficult to define what is positioned ahead of what - who is at the head of the column and who is near he tail end of it.