Hopefully you don't feel put off by my short response. I want to clear up the distinction between Communications Management v Stakeholder Management. What stands out from the Project's I've managed and what I've studied is CM is holistic planning, preparation, and distribution of information throughout the project/phase of project. Stakeholder Management incorporates the CM as an input because there will be a planned way to communicate, but overall the SM is about ensuring you have support throughout your project. So you use this knowledge area on how to devise that need. Here's where stakeholder analyis is vital. Knowing the information needs of your stakeholder will enable you cater to the way they want to be information, thereby ensuring you have their continued support. Also, there are stakeholders who may not support your project, but are affected by its outcome. You've got to manage them in a way that prevents their role as obstacles to your endstate.