Any project requires communication and information flow that has to be infused into the team in a systematic and scheduled manner. Information related to assignments is critical to the project success.
If the information is not given to the right person, at the right time and in the right manner, the entire assignment stands at risk. Therefore, it is important that the Project Manager should work as a single point of contact for any assignment.

Also, in an assignment with different stake holders, it is a possibility that each of them have a different idea and thoughts about the project. This may lead to a scenario where the team is getting information from all the stake holders, and the lower rung team members are quite confused about what to follow. Therefore, the project manager should act as the single point of contact, and any information provided through the project manager should be considered as final and binding. Being the single point of contact should be one of the most important responsibilities of a project manager.

这个在做项目的时候特别重要！是项目经理要做的重要工作之一。

About definition of Single Point of Contact:
1. A point of contact (POC, also single point of contact or SPOC) is the identification of, and means of communication with, person(s) and organizations(s) associated with the resource(s). A POC can be a person or a department serving as the coordinator or focal point of information concerning an activity or program.

POC’s are used in many cases where information is time-sensitive and accuracy is important.
2. Central communications office, phone number, or website that channels all incoming messages to their appropriate destinations.