Well, everyone knows what social media is, and depending on your audience, you may choose one or many avenues to reach out to customers.
Facebook, Twitter, Google+, Foursquare, Instagram, Pinterest, and YouTube (just to name a few), are all relatively inexpensive, if not free, ways for a business to engage with their fans and customers in a manner that was not possible even 5 years ago.
Exploring how other businesses have used social media to promote their brands, as well as seeing how the use of social media can backfire if not handled properly, is a worthy subject for any business to pay close attention to.
Learning how to use these sites to the best of your advantage is a simple and convenient way to reach out to customers.