According to Diffley et al. (2011), the difference between a consumer and prosumer is that “the prosumer is highly knowledgeable about products and services and can play a key role in improving these products and services” (pp. 49).
Bearing that definition in mind, I have taken two cases as examples. The first one is a platform launched by Starbucks, http://www.mystarbucksidea.com. Consumers can submit ideas for Starbucks to implement, and can vote and comment on each other’s ideas.
The second example is about the campaign by Warner Bros for ‘The Dark Knight’. Warner Bros created a viral campaign that merged the online and offline worlds in a spectacular way, directing their fans to numerous addresses at which they fulfilled tasks in order to join the Joker’s Army. If you are interested, check out http://www.voxmagazine.com/stories/2008/06/26/building-jokers-army/ and http://www.whysoserious.com.
All in all, both ideas are very successful, but there are some drawbacks to every case. Starbucks needs to be on top of its website in order to prevent customers who have submitted their ideas but received no credit for it from becoming frustrated. In the case of Warner Bros, the fans were not really creating content themselves; however, they were fully engaged with the brand.
I am curious to hear what you guys think about these two examples!
Social Media and Social Networks 
I think Warner Bros did an amazing job when it comes to audience participation; they really went out of their way to engage the fans in their campaign. But isn’t it that most activities were only interesting to fans that were REALLY excited for the movie? There’s a lot of ‘work’ involved in getting al these clues, and it’d take some dedication to do all the required things. My guess is that the general audience wouldn’t immediately participate in such a campaign. However, I never knew how detailed and big this campaign really was, so thanks for pointing that out 🙂