In a post about three and a half years ago, I wrote:
Publishers serve three important functions:
1. The physical production and distribution of books.
2. Assisting authors in writing books.
3. Filtering books, selecting from the very large number that potential authors wish to write a small number to actually be published.
I pointed out that the first function was no longer necessary, given the ease with which an author can publish his book himself by webbing it (as I have done with several books) or by using an online Print on Demand service (as I am in the process of doing via Amazon's CreateSpace for a collection of medieval and renaissance recipes). If I were writing that post today I would add a third option—selling your work as a Kindle file on Amazon, as I plan to do shortly with my second novel. The second function is useful, but it does not require a publisher. Copy editing at present is largely done by free-lance editors; there is no obvious reason why other forms of editing could not be. The best editorial assistance I ever got came not from my editor but my agent.
That leaves only the third function, and I suggested that there ought to be some way of providing it via decentralized sources of information online, as Google presently provides the analogous function of identifying which pages best match your search criteria. My elder son was, at the time, working for Google; one commenter on the post remarked that when he went home for vacation, all his mother expected him to do was to take out the garbage and shovel the walk. I expected my son to abolish the publishing industry.
It appears that the job is already being done, and not by Google. I recently came across a webbed description of how readers of fan fiction, amateur stories set in the world of Star Trek, or Harry Potter, or other well known works of fiction, solve their problem of sorting out the treasure from the trash.