Why is the development of a communication plan so critical to the success of a Project?

Topic 1: Project Management is not just doing tasks and you have success. There are many critical aspects of project management relating directly to communication.
Visit the Tech Republic website listed below:
http://www.techrepublic.com/blog/project-management/communication-plans-are-key-to-project-success/1537
Read the article: Communication plans are key to project success
Answer the following Questions:
Why is the development of a communication plan so critical to the success of the Project?
In your current business are there any specific communication quirks that would need to be addressed in your project communication plan? Explain
In your own opinion are there items that you feel are very critical and others may not see the value If so why are they important and as Project Manager will you add them to the Communication Plan? Explain