There is one area where POD works big-time - Production of a textbook for a niche market too small to interest textbook publishers. My book with iUniverse on research methods cost me $400 and made me about $9000 (close to 3,000 copies) in 4 years. I have now produced a second edition.

To do this, you need: 1. A known market 2. A strong means of informing your market of the book's availability.

I have not seen any serious delivery problems emerge. Quality is a bit week, but textbook readers don't seem to mind if the content is there.