The entire publishing industry has nothing but scorn for self-published authors who submit e-books with no ISBN number. These titles belong to the shadow realm, because its impossible to track metrics and sales data.
ISBN numbers are critically important for an author to claim ownership of their work and support the self-publishing movement. Over the course of 2014, 30% of all e-books being purchased in the U.S. do not use ISBN numbers and are basically invisible to the industry’s official market surveys and reports; all the ISBN-based estimates of market share reported by Bowker, AAP, BISG, and Nielsen are totally incorrect.
Data Guy is the big data expert who compiles e-book sales from a myriad of sources and posts his findings on the Author Earnings website. In New York City he gave his first lecture and had some very interesting things to say about self-published authors with no ISBN numbers.
“Do we care as an industry about small and non-traditional publishers?” he asked. “We run the risk of leaving money on the table, or not seeing competitive threats,” if what we’re working with is an incomplete picture, he answered.
Data Guy is right, it is very hard to get a sense of emerging trends and hot new genres, if there is no way to monitor them. The Amazon terms of service for their Kindle Direct Publishing program actually forbids authors to talk about their sales and if they are found guilty of disclosing this information their accounts are suspended.
There are numerous people that think that ISBNs are necessary for physical books, before retailers still require them. Whereas ISBNs are no longer necessary for digital books, because retailers no longer require them. Apple was the last holdout, and stopped requiring ISBNs in 2012.
The causal reader does not search for e-books using an ISBN number. Oh, there are exceptions, such as college textbooks where you have to be sure to have the right version. But in general, readers don’t use ISBN. At all. It’s an industry tool, used by retailers, distributors, and publishers, which adds nothing to the user experience of the e-book. So if distributors and retailers stop using ISBN numbers, the only reason remaining to use one is is because publishers still use them.
I think its critically important that indie authors invest in ISBN numbers for the overall health of the digital publishing industry. Self-published titles went from making a few million dollars a year a decade ago to generating hundreds of millions in 2016. If these titles are not included in industry reports from Bowker or the American Publishers Association they might as well not even exist.