If you choose to publish only on KDP, your ebook will be available only at Amazon. Amazon’s share of the global ebook market is high, but on the long term, it is worth working with many stores, just to have more feet on the ground. According to our current sales numbers, Amazon contributes to 45% of the global ebook sales, while 55% happens elsewhere. We strongly advise you to publish your ebook in many other stores, such as Apple iBooks or Google Play and on new, subscription based platforms, such as Scribd. This way you can immediately reach billions of readers who have these apps preinstalled on their devices. Please note that the more stores your books appear in, the higher your SEO results and Google ranking will be, which can result in higher sales numbers.