Perhaps there's a somewhat fluid & ambiguous zone -- at one end of which, we can say coolness is simply a term for a certain species of esthetic judgment (a judgment that's variously constructed as individual or collective, or that may have elements of both) -- while at another end of this zone or spectrum, the very notion of coolness & who's in or out of the club may seem a somewhat artificial / media-mediated social-status phenomenon. In some ways coolness is perhaps largely a term for perceived esthetic excellence: it's certainly applicable to music to writing, to art in general, and to the realm of expressed ideas.

One whole topic I want to address (I've not really had time to get back to this in the past day or two) involves "the limits of the cool": various ways in which a sensible or thoughtful observer may find her/himself disposed to disavow or step back from the whole category / concept: a thing which can happen on various grounds, no doubt. If coolness [that is, the perception of this quality] is in some sense manufactured, is a sort of PR stunt, to what degree is it mere artifice? In certain fields (I guess mainly pop music & the movies), a lot of money hinges on such perception-manipulations.

Anyway, this is possibly a tangled sprawl of a topic. On top of which, I now feel some need to look into the etymology / origins [or "oranges" as one former Prez used to say] of the term per se: to see when it first appeared in this specialized cultural usage, etc.