Social media is a new paradigm of marketing, it's requires a different approach to marketing.

http://www.webbizideas.com/social-media-strategy-3-main-principals

It's 'always on' and contains elements of instantaneous communication. What we call social media should be more accurately termed social communication. Humans are social animals but what changes is how we communicate with each other. Social networking allows us to communicate instantaneously across the world in a matter of seconds. It also offers a direct one on one or one to many connections that has never existed before.