Basically, crowdfunding is a way of funding a project with micro-payments from people who are willing to invest in your project. Authors use crowdfunding as a way to finance their work on a book project. The author’s goal is to get funds for editing, cover design and promotions; or, the goal may be funds for living expenses while he writes a book.
If you know you need money for your book, crowdfunding may be an option for you. It's not for everyone, but investigating possibilities can't hurt.