The way I look at it is that the scrum master is much more of a facilitator than the project manager is in a traditional project. Also in Scrum there is a product owner who does much of the type of work a traditional project manager would do. In a way, the "project manager" role in Scrum is split between the product owner, scrum master, and the team itself.

Both of these roles are a bit dynamic so it's difficult to compare, but that's my best short answer.

Josh Nankivel pmStudent.com

I agree. What the scrum master is managing is the "sprint", not the actual project. The sprint is part of the development process which, in turn, is part of the project execution process. The project execution process is just one part of the overall project management life cycle and is just one of the many things that a project manager must manage.

Scrum is not a project management standard or methodology. Rather, it's an application development methodology, primarily used for I.T. and technical projects. It's the I.T. equivalent of a product development methodology, not unlike older, traditional I.T. methodologies such as SDLC, waterfall and Microsoft Solutions Framework (MSF). It is a management tool, but what you are managing are the technical development tasks.

Jerry Bucknoff, MBA, PMP

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