The following article highlights three businesses and their success in utilizing social media to engage and involve their customer base.

The “New Basics” Of Social Marketing Strategy And Standards
Online retailers today are racing to adopt social strategies, seeing them as a key to a more engaged customer base, a lower customer acquisition cost and a higher brand affinity. As retailers assess this opportunity, their hopes are that these improved
methods of interacting with customers yield greater sales, higher margins, faster growth and increased competitive positioning . . .

http://www.adotas.com/2012/07/the-new-basics-of-social-marketing-strategy-and-standards/