Print-on-demand (POD) publishers, such as Xlibris, iUniverse, and AuthorHouse, are the same as subsidy publishers, except they use print-on-demand technology. They rarely use traditional print runs, and your book is not printed or produced until it is ordered. Their upfront fees usually include the cost of getting your book set up in their system; any design, production, or editing work they do to prepare your book for publication; and other add-on services such as editing, marketing, promotion, advertising, etc. It’s very affordable for most people to publish through a POD service, since the production cost plummets when you don’t have to pay upfront for a traditional print run.
Some POD publishers claim they’re not subsidy presses, but rather a new form of technology that empowers authors. But their model is exactly the same as the “old” subsidy presses: For a fee, they’ll publish your book and make it available for sale. Your book is not stocked in the bookstores, though it may be available on Amazon’s site. In contrast, a traditional publisher employs sales reps who call on the bookstore buyers to make sure all of their books get placement in stores; this does not happen with any POD or subsidy presses, who do not have sales reps who call on the bookstores.
Sometimes you can get your POD book stocked in a handful of bookstores if you approach them on your own, and some POD companies have relationships with bookstores that are willing to take selected titles. But this is not the norm. Bookstores have a bias against most POD publishers, since there’s little or no quality control as far as the material they publish, the books rarely have the same quality look and feel as the traditional houses’ titles, and few POD companies offer books on a returnable basis, which all bookstores expect.