The Product Owner’s role is to ensure the right features make it into the product backlog. The product owner is typically a project's key stakeholder. It is important that a product owner have a vision of what to build and that the product owner be able to convey that vision to the team.

Besides providing direction, the product owner is commonly a lead user of the system or someone from marketing, product management, or anyone with a solid understanding of users, the market place, and the competition.

Besides being a facilitator, the scrum master makes sure the project moves forward in a smooth fashion, plus ensuring every member of the team has the tools and resources to get their job done.

This person sets up the meetings, monitors the work being down, and facilitates release planning. They remove the barriers between the development and the product owner so that the product owner directly drives development. Think of this person as a Project Manager.