How well you interact or even survive in the world is determined by your ability to receive information, process that information, and take appropriate action based on your perception of the information.
Those who have the skills to listen well have more complete and accurate information about their relationships than those who do not.
They are likely to get more of what they want in a negotiation because they have the benefit of complete and accurate information.
Why is listening important? If it's true that communication and conflict are intimately related, and listening is essential to communication, it follows that listening is critical to the management of conflict.
More on listening...