I think that the publishing world and the writer's place in it is changing radically. Advice I gave just a few months ago I'm finding increasingly less helpful. Things are changing and changing fast.
The "real" publishing world has been dealing with print on demand, self-publishing, and "instant publishers" (a publisher who appears just to print a title or two, then disappears) for a while. When I was keeping track of writers eligible for the John W. Campbell Award for Best New Writer, we talked about what to do with a print-on-demand title that might take several years to cross the 10,000 print run threshold that was the standard for a professional pub at the time.
The problem of defining what is a "professional" publication has only become more challenging since.
Personally I think the publishing houses will still remain the "star makers" for some time. They have the name and the reputation for publishing winners that will continue to attract readers, but I also believe there will be more and more outliers, the writers who manage to attract readers through non-traditional venues. It is much more possible now for a self published writer of sufficient talent and chutzpa to find many, many readers and make serious money.
I would still argue, though, that WAY more writers think they have the writing licks to do that than actually have developed their craft sufficiently, and they tempt themselves right out of the competitive kiln that is traditional publishing, and because of that they vastly reduce their chances of becoming competitive.
E-publishing is producing way more noise than signal. Readers don't have the time to wade through the chaff of the self-published to find the "wheat" titles to read. They are going to rely on publishers with a reputation for quality to put good work before them, AND they're going to rely on good reviews, word of mouth, and probably some burgeoning social network of readers to find the good work.
For most unpublished writers, the "success" of the self-publishing world is as unobtainable as the dream of traditional publication. Putting their works up on Amazon won't guarantee them readers or money. Who is most effected by the changes in publishing right now are the previously published writers, the ones who have an audience and a track record of worthwhile writing. Those writers are the ones who have to ask themselves the question of where their work would best be showcased to both attract the most readers and make them the most money.
Any previously successful writer has to look at Amazon's 70% royalty on any sale of a book that costs $2.99 or more and be tempted by it. That's significantly more money than they make per book with their traditional publishers.