The stakeholder plan is in place to ensure that all stakeholders are identified along with their role, interest and influence into the project and a engagement strategy is in place.
Based on stakeholder role, interest & influence they may be a passive stakeholder, one who is supplied with status reports and kept in the loop as to the progress of the project or they may be an active stakeholder that is one who approves modification to the project plan, participates in status meetings and provides input and feedback throughout the project.