How social network influences e-commerce sales?

As I told in this post in Portuguese, I have started the research for my final paper in my MBA course. I’m not sure about what specific area I will research but I think that the suggested title “Social network influence on e-commerce sales” means much. First idea is test some different approachs and monitor them to see how consumers drive to a goal and which strategies are the best in each case.

This work will be done along 2012 and I would appreciate if you could help me telling your experience about successful cases where good social networking strategies resulted in sales boost on virtual stores. As I work only with Magento, the virtual store must’ve been built using this platform.