Ellen Birkin talks about how acting is about telling secrets and revealing a little more in each scene.
Social marketing is very similar - each post, each tweet, each interaction is a window into your brand's personality.
Free can also be used as a revealing tool - show enough to create interest but not enough that you stop people from wanting more...
Free is not about giving your product away, for me it is about giving your personality away...to encourage people to want to trade up for more.
Social marketing may have been seen as a revelation for consumers...but I would argue the revelation is both in what it can achieve but also in what it can reveal about you.