I read and hear so often that POD is self-publishing. Even when people are told the difference between POD and self-publishing, they won't stop using POD as a synonym for self-publishing. THEY ARE NOT SYNONYMOUS.
I'm going to try one more time to explain what POD, print on demand - not publish on demand, means.
First of all, POD, digital printing, is a form of technology that is used to PRINT material. It is not a type of publishing, even though it is often used by publishers and by people who self-publish.
We can find print on demand publishers or print on demand services, but those names simply mean that they use digital technology, not that POD is what the publisher or service provider is called.
Digital printing allows a complete book to be printed and bound in a matter of minutes. The process is used for smaller numbers of books to be printed. Offset printing results in a lower cost per copy, but a much higher initial outlay, because 1,000 or more books must be printed per run. Digital is technology that works better for smaller runs. Offset is not cost effective for small runs.
So, if you use the term POD to mean self-publishers or self-publishing, don't be surprised when I scream.