The role of Stakeholders is to provide feedback on the product being developed. Stakeholders are people who have an interest in the product but are not actually producing it. Some potential examples of stakeholders include:
These are key contributors to the product backlog. In reality there are two classes of people here - the customer and customer proxies. Also note that the disciplines (such as Development, Certification, Internationalization / Localization and Documentation) are typically considered “stakeholders” when there are activities that are not directly involved in “implementing”.
The primary role of stakeholders is to provide feedback to the Scrum Team. In particular the Product Owner uses the information provided by stakeholders to adjust the Product Backlog.