What Is the Core Principle of Social Media Marketing?

I attended the Social Media Marketing World Conference 2014 in San Diego (#SMMW14).  I heard many case studies and real success on social media marketing, which were drawn from different industrial sectors and represented a variety of social media platforms.  In the end, I made one conclusion: Listening and responding to customers is the core principle of social media marketing.  Companies now can answer the following questions by analyzing the consumer data on the Internet:

• For what purpose or on what occasion do customers use a product/service?
• What do they like or dislike about a product/service? And for what reasons?
• Who is actually buying and using a particular product/service?
• When is the best time to communicate with the target customers on social media?
• Where is the best "place" to reach the target customers?

Is it that simple?  Just "listen" to what customers said online, and then "respond" to what they need?  Check out my reflections on #SMMW14.