Book metadata is important to your book's categorization, discovery, and overall book sales. It should be part of any author's overall book marketing strategy, and successful self-publishers know how to incorporate as much quality metadata as possible into their sales plans.
Keywords and phrases that you use to describe yourself and your book are metadata. Your book metadata will consist of basic things such as your title, author name, author bio, book description, publication date, etc. Keywords are one or more words used to indicate the content of your book. Metadata and keywords are what make your book appear when a reader goes looking for a specific thing, whether that thing is a book or not.
Search engines use metadata as an information retrieval system to connect searchers with content and products more efficiently than ever before. To search engines, all words have a value, and keywords and phrases have even more value. Strategically select keywords that best describe your book. If your book is about the best hiking spots in Colorado and someone types that into their browser, they may not have known they were looking for a book specifically, but if you’re using the right keywords and your book is displayed as a resource to that user, you could potentially make a sale for being in the right place at the right time.