E-books continue to maintain a steady share of the book publishing market. By 2018, e-book sales are forecast to account for about a quarter of global book sales. (https://www.statista.com/topics/1474/e-books/)
www.Statista.com provides one of the better summaries of the e-book market I’ve seen:
“E-books have found their place in the hearts of American bookworms – 13 percent of book readers in the U.S. stated they read more e-books than hard copy books, and 15 percent read about the same number of hard copy books and e-books. In 2016, about 73 percent American book consumers stated they read books in any format, and about 30 percent stated reading at least one e-book in the past year. This consumption also has a positive reflection on revenue generation. Between 2013 and 2018, revenue from e-book sales in the U.S. is forecast to nearly double. Daily sales of e-books of online retailer Amazon in the U.S. alone stood at more than 517.5 thousand units as of January 2016, with e-books published by independent publishers accounting for the largest share of this total. Popular e-readers among U.S. publishers and authors include Amazon’s Kindle, Apple’s iPad, Barnes & Noble’s Nook, and Kobo, an e-reader produced by Canadian company Kobo Inc.” (https://www.statista.com/topics/1474/e-books/)
When it comes to e-book marketing, authors often ask if we promote e-books differently. The short answer is no; we follow the same promotional approach regardless of how a book is published. The delivery of a book when requested by media is different, but everything else remains the same. We’re also asked if having an e-book in addition to a printed book is essential as it relates to author promotion. While it isn’t imperative to have an e-book, having your book available in more than one format can only help, and creates an additional sales channel.
A book available in print only is also fine, and doesn’t affect how an author publicist approaches promotion.
When media request an e-book, we often use a NetGalley link that allows easy access to an electronic version of a book. There are also bloggers and online reviewers who specialize in reviewing only e-books.
Books published as e-books only can often benefit by focusing on other non-publicity marketing, such as Amazon Kindle pricing programs in which a book can be offered for free for a set period of time, and then the price is increased in intervals. (https://kdp.amazon.com/en_US/help/topic/A34IQ0W14ZKXM9)