POD is a process: Print On Demand. Any printshop running a digital press — such as a DocuTech, an Indigo, an iGen, a Nuvera — can provide POD services. They print only the quantity you need. There’s no minimum of 500 or 1,000 copies. Kinko’s and AlphaGraphics are POD shops, just as Lightning Source is. By the way, Lightning Source isn’t a publisher and doesn’t call itself one.
The companies that facilitate on-demand book printing and delivery, like iUniverse and AuthorHouse, aren’t PODs — they’re POD publishers, also called subsidy publishers. (And don’t let these companies fool you — you’re not the publisher unless you own the ISBN.) POD describes the process they use.
Don’t take my word for it: