There is an interesting distinction between prose and poetry writers and their attitudes to ideas. Poets without inspiration can do nothing, but can pursue any idle thought without investing too much time; they therefore tend to be passive and, if uninspired, concerned. Prose writers will usually have more ideas than they have time to deal with, and therefore treat the writing process as more of a routine chore. This doesn't, however, make them any happier about talking about a work in progress.
For a start, there is the superstitious fear that saying out loud that it's going well will be the cue for it to stop. Then there is the more rational advice that if you tell somebody about how the story ends, you will lose all interest in typing it, since you have reached the conclusion. But the biggest stumbling block is trying to capture the nuances of the tale which reaches beyond bald plot summaries. I remember seeing a discussion about the value of writer's endorsements on the c0ver : 'I wished I'd written it!' - Dan Brown. The conclusion was that publishers are very keen on them but buyers aren't: they ignore them. What they want, and are often denied, is an idea of what the book is about.
I'm not sure, though, that this really helps. When I say on the back of File Under Fiction that it has a story about a gentry family living on a country estate, I presumably may arouse the interest of fans of Evelyn Waugh, Jilly Cooper, or Joanna Trollope, but most of them would be disappointed. The danger is that in the abstract most stories sound dull - imagine a novel about this big shark, that eats some swimmers, and then is caught; or, a whaling captain tries to catch a whale; or an old man tries to catch a big fish. None of them sound like winners, really. You really do need some sort of meta characterisation about pure plot, to give readers hints about the sort of book it is.
These days most of this information about style is provided typographically: chick lit books are instantly defined by the zany font and colour scheme, just as thrillers will have short titles in bold letters. Although this can be convenient, it does tend to ghetto-ize people's reading habits, so that they only read the sort of books they have read.
The reason I'm thinking about this is that the book is finished, and at 180 pages is something you could point at as something substantial, something that could be marketed. But who to? But another reason is that I feel I've reached a natural end-point; I have been working on and off on the long stories for five years or more, and now they're done I'm wondering what's next. I've got some ideas, but they would sound even stranger than the ones I've completed. But one thing I have noticed recently is that I really can sit down and write: the Dylan story was complete in outline in my head by the time I was back home from the gig, and complete on paper the next day. So whatever it is, it should go smoother.