The trait of being excited and and pleased by novelty. Common trait of most hackers, SF fans, and members of several other connected leading-edge subcultures, including the pro-technology `Whole Earth' wing of the ecology movement, space activists, many members of Mensa, and the Discordian/neo-pagan underground. All these groups overlap heavily and (where evidence is available) seem to share characteristic hacker tropisms for science fiction, music, and oriental food.
In this sense, neophilia is essentially continuous with a belief in at least the possibility of progress, and it would be absurd to claim that was recent. What is recent is the complete loss of history and tradition, and the resulting sense that everything is new, unique, without precedent. New is not just better than old: the old is not even known to have existed.
This attitude is the logical successor to what philosopher David Stove calls the horror victorianorum of the early twentieth century, the intense and terrifying feeling of being strangled by the past, especially the nineteenth century, which became epidemic in the West after the First World War. The past was despised and rejected, its legacy hideous and to be destroyed at all costs, and to this task the modernists applied themselves. In conjunction with the rise of the mass, electronic media, they were astonishingly successful, and to ``deconstruct'' or ``subvert'' tradition these days is to flog a dead horse.
A true post-modern admits that the world existed more than twenty years ago, and has some vague notions about what happened then, but in her heart of hearts neither believes in nor cares about the past. Some claim to pay attention to the past, but always to a very distant, and frankly very mythical, antiquity; the most extreme case is perhaps that of those members of Earth First! who embrace the slogan ``Back to the Pleistocene!'' They view the history of all hitherto existing society as set once and for all in (as Mircea Eliade would put it) illo tempore. Except that they also believe that great things are happening now, that this is another illus tempus, in which the world will either be destroyed or renewed. Thus the members of Earth First! would have us believe that at last we can reclaim the happiness that was ours as purely ``natural'' plains apes twenty millennia ago. Even this degree of historical awareness is uncommon.