Self-publishing and vanity publishing can be very difficult to tell apart.
There are marked similarities between them: both often involve little or no editorial selection or input; both usually produce books which are difficult to market or sell effectively; and very few books from either sector make a decent number of sales. But there are differences too.
Self-publishing involves a writer publishing their own book, and controlling everything from the content to the sales. So the imprint on the copyright page has to be theirs, and not that of the publishing service they’re using. The copyright statement refers directly to them, or indirectly by referring to the copyright holder (who happens to be them), and not to the publisher or printer. If a book is published with someone else’s imprint on the title page, it can’t logically be self-published, right? Further, the self-published writer maintains control of the editing, production, PR and sales processes all the way along: while they might pay other people to do some of the work for them—like editing or design—they project-manage the whole thing. This means that at any stage in the process the self-publisher knows exactly what’s happening with their book, how many copies are printed or sold, and how much profit or loss has been incurred as a result.
As I’ve written before, a vanity publisher is defined as a publisher which makes the majority of its money from its writers rather than its readers, whether by up-front charges or through selling books back to them once the book is published (which is how PublishAmerica does business). It’s a question of focus here, and websites are a good source of information: if the publisher focuses on finding new readers to sell to, chances are it’s a mainstream house; if its focus is on impressing writers and getting them to submit then chances are it’s a vanity press. Writers who use a vanity publisher have little or no control of the publishing process, they usually don’t have easy access to sales or royalty figures, the imprint on the copyright page is rarely theirs (although I have seen this happen) and often the copyright statement doesn’t refer to them either. Then you can argue that there’s a question of intent on behalf of the vanity publisher; and a question of the author’s knowledge and understanding of the process—but those two points are much more difficult to quantify and establish, and sound either spiteful or insulting, depending on whether you’re the publisher or writer concerned, so I’m not too fond of them.
This is a difficult distinction to make. It’s made even more difficult by most of the vanity presses insisting they’re self-publishing service providers, subsidy or cooperative publishers, or are working to a new business model or other similar nonsense; and by writers not understanding that there are so many differences between mainstream, vanity and self-publication. Many organisations don’t distinguish between vanity and self-publishing: I remember hearing that the Arts Council, for example, lumps them in together. But I know of several dedicated self-publishers who do very well for themselves; and I know of many writers who have been stung by vanity publishers and have been deeply hurt as a result.