It seems logical that after an initial run of books or after a set period of time, a book would be transitioned to print-on-demand. This allows for the publisher to continue selling titles without maintaining a massive inventory. Ingram markets Lightning Source to publishers for this exact purpose.
Let’s take this opportunity to clarify some of the terms that might be getting used interchangeably:
Ingram Content Group is a conglomerate of services targeted towards authors and publishers.
IngramSpark is the self-publishing arm of Ingram Content Group
Lightning Source is the printing arm of Ingram Content Group used by IngramSpark and others. In fact, this is the same printer that you get if you leverage Barnes and Noble Press for your self-publishing.
Ingram ID is their advertising arm that will help you deliver ads to verified readers.
They offer more services than this but these are the services we’ve investigated so far. Another service was Aerio, which was a great digital storefront service, but it was shut down in January.