This book is an easy and useful choice for web developers who have some experience coding APIs. Even if you don't plan on creating a huge service involving partners and creating a specific community of developers around your product the book, especially its first half, encloses a handful of reasonable ideas, good practices, and clear explanations that will help you build a cleaner, better structured and, ultimately, more useful APIs.
Nevertheless, coders beware, this is not a book about code. Probably it's more oriented to product owners, architects, and team managers. But having a broad view of the larger picture behind all your code. It's always good to have many of these chapters in mind.
Maybe the final chapters of the book become a little bit too long, not adding so many insights, at least for those who get their hands dirty on the keyboard. Also, the examples and testimonials included, after feeling rather attractive and insightful in the first hundred pages, end up turning repetitive and a little too propagandistic. But apart from that, this has been an interesting reading.