I've been working for self-published authors pretty much from the beginning of my career. In fact, for seven years, I ghostwrote books for a guy who started his own company just to self-publish his own books. We were extremely successful (for the world of publishing). Let me put it this way: he owned his own jet based on his book sales. Not bad, right?
Later on, I signed on as a contractor for the largest POD companies in the industry, where I provide editing services for self-published authors who select that option as part of their packages. I've worked with hundreds of authors on their books, which range in quality from needing loads of help to quite good. Especially lately, I've noticed that the quality of books crossing my desk seems to be rapidly increasing.
I think this is an exciting time to be in publishing ... it's not often you get to witness the mass democratization of a whole medium. But it hasn't been exactly easy to wrap my mind around what's happening. For one thing, having actually read enough self-published titles to have an opinion, it's true that many, many self-published books just aren't that good. The stigma against self-publishing was earned; it's not the product of snooty New York editors looking down their noses at rambunctious competition. It's because the majority of the books aren't very good.
And yet, that doesn't mean self-publishing itself has no place in the industry. In fact, it's growing more and more important as the stigma fades and people like JA Konrath and Amanda Hocking show that you can make good money and have a good career without a publisher. Like Erica said on her blog today, they're proving something that nonfiction writers have known for a long time: there is no single path to success in publishing, or even one single definition of success.
So looping back to Editing for Authors ... here's how I view the editing process: when an author hands over a book to an editor (or a critique partner), they are handing over something very precious, something they might have invested years of their life in and sacrificed time away from other pursuits to produce. It's not my job to tell anyone their book is good or isn't good ... it isn't my job to "fix" anybody's book (unless we're talking about grammar and spelling, in which case it's very much my job). It's my job to do whatever I can to help that particular book become the best book it can be.