Significant diversity can exist in the activities, operations, size, and legal structures of not-for-profit entities. There is also significant public interest in the accountability of not-for-profit entities, because they are generally supported by voluntary contributions of both physical and financial resources and their purpose is largely to serve some public need, as opposed to being in business for profit. To varying degrees, such characteristics impact on the audit of not-for-profit entities, including the audit of fundraising revenue.