At the outset of my self-publishing journey, in 2008, there was this site, "Bookhabit". You could self-publish your book as an ebook up there, which is what I did... for the first 5 Solar Wind sequels. The 6th was in progress when I got sidetracked into paper-publishing & starting P'kaboo. (The other place I uploaded to was Lulu.com.)
Clare Tanner was the owner of Bookhabit. She had something going: People bought ebooks at $2.99, and the author got a $1 royalty per sale. That meant, $1.99 profit for her for every sale. Also, she paid out after you had a minimum amount in your account ($50 I think it was?). I never got that far. That side of things of course goes under loose ends; I also think her profit margin as compared to author royalty was a bit big, considering that there was no running cost (other than the web hosting). In the light of Kindle having a 70% royalty program, and EPub and some other sites allowing you to keep all your royalties, one would expect service from a place like Bookhabit.
Service she did give. She got in touch with authors and helped them tirelessly with their upload issues etc. She didn't review the books unless they peaked her interest (there were over 600 titles and I do believe the intent was to read them all but of course she needed to select). I was amongst the lucky few whose books she actually read and I hope sincerely that this was worth it for her, as mine weren't exactly runaway sellers. She did call me, all the way from Australia, to put up a podcast for me. I (stupid me, newbie) said all the annoying things first-time authors say, like, "I hope the books will get as famous as Harry Potter", and going on to discuss the whole plot. I hope since then I've wised up a bit, poor Clare, she was working with absolutely raw material there.
Clare had something there. She definitely did. The concept of publishing books as ebooks only, and then presenting paperbacks of same when the sales figures warrant it, really teases. I wouldn't allow people to self-upload (yet); they'd have to submit. For Kindle, you self-upload and an automated system checks your files; and then they get re-checked, I don't know whether via a more sophisticated system or actual people but the latter seems likely, seeing how they "fix issues" with minimal fuss. But: Nobody proof-reads your story and tells you it's sub-standard. Nobody refers you to an editor. Nobody physically does the layout for you (unless of course you contact those people on Kindle yourself and ask - and pay - for those services).
Now, P'kaboo would do it differently. We'd actually read your manuscript (so it's a full submission). We decide whether it's up to our standard and within our scope (I've to date read a couple of very well-written manuscripts but their content fell outside of what P'kaboo wants to represent, whether they were violent, overly political, or in other ways didn't suit our concept - so if we reject your book, try submitting your other book, it might be more acceptable). We'd do the internal layout for you, to publish the book on our site as pdf; and later, when the machinery is in place, as DRM-managed Kindle, Ipad, Kobo, Nook etc etc files. We would then also place your book in such stores as Amazon. If you need editing you can get it from our Author Services. Also the cover graphic is something you need to consider.
In other words, you'll not be self-publishing your ebook. You'll be getting it polished and perfected, and promoted into various places, and most importantly, you'll have been approved. You'll be published via us. Your book will bear our logo. And in time, if the sales figures warrant it, there shall be a paperback of same.
Let me put my mind to it.