Some days it seems that for every eBook writer there is an eBook publisher. Ok, so the equation might not be that balanced, but it sure seems close.
The ease of publishing an eBook is what has driven this proliferation of eBook publishers. Although the process is now easier than it has ever been (as far as actually getting your eBook to market someplace) it is still beyond the ken of many.
Much like traditional publishers, eBook publishers help you properly format your book, create and/or select a cover; perform edits for content and/or grammar (some more, some less) and help you get your eBook listed and in front of as many potential buyers as possible. These new eBook publishers will also help you market your book using their existing networks.
There is no way to accurately gauge the impact of one eBook publisher over another simply because there are so many and they perform such a wide range of functions. It is clear from their many and varied offerings that specialization is the name of the game. Some of these eBook publishers are focusing on free eBooks, while others are focusing on serialized novels; some are honing in on the academic market while others are looking to expand global consciousness with public service eBooks.
If you have an eBook, there is definitely an eBook publisher that wants to talk with you.
Which brings me to my point: the success or failure of these eBook publishers will hinge not so much on their abilities to promote or network, but rather on the quality of the eBooks they publish. Ultimately, if a book is popular it will sell. Period. And the reverse is also true.
This means that eBook publishers, much like traditional publishers are not much more than agents for talented authors. They help readers connect with books, but said content is merely a commodity for them to trade, not a product of their effort.
It seems to me, if you have a quality eBook you should consider self-publishing it. If it's good enough, people will find it and buy it. If it isn't, they won't.
Really, it's as simple as that.