These days readers consume books in various formats. Some prefer paperbacks, others won’t touch anything that isn’t on their Kindle and others like to read books in PDF on their computer. When you set up your sales page for your book make sure you tell your readers how and where they can buy the book in any format you offer. For example, put a buy link for physical copies and link to the Kindle and Nook. Make it easy for your readers to buy your books no matter how they intend to read them.