The last year has seen the creation of what is generally understood to be a "social contract" for social media, according to David Kidder of Clickable: if you establish a relationship with a brand by being a fan, you agree to share some information in return for some kind of reward, in the form of coupons or promotions etc. Brands that don't get that, and fail to provide some kind of reward or acknowledgement (however small) won't succeed in building their social media presence.