What is the role of the Scrum Master in an agile project?

This can be a follow-up to an earlier question which asked you to define the individual roles within an agile project. Providing additional details demonstrates your knowledge of this role and perhaps qualifies you to be assigned as the scrum master once you obtain the job.

"The scrum master is the leader of the project as well as the coach for the entire team. They have several responsibilities, including motivating the team, monitoring their performance, and removing any roadblocks which would impact the project. The scrum master must have in-depth knowledge about scrum, agile, and any other frameworks used to complete the development project. They are also responsible for process improvements and communication with the product owner."