While at PodCampNYC, Chris Brogan shared his social experiment idea he created while reading Social Intelligence.
"Your are the first to hear of this. So you're one of the few. When you hear the word 'Hey!', smile your biggest stage smile. Make it big.... And, only tell a few people."
Chris read that smiling releases certain chemicals that make you feel better and that that smile also effects those around you, making them feel better (See some researchy stuff at PubMed: Communicating With Patients: What Happens in Practice? or even better PubMed:Interpersonal consequences of social anxiety).
What is also interesting in this experiment is how it is set up. Chris made me fee special by letting me in on a secret. I have no idea if I was the first to hear the idea but his approach made me want to hear the idea and then to share it with others. I told about 10 other people that night.
This is a simple example of using a social network to spread an idea (Idea Virus as Seth Godin calls them). The virus was the smile combined with the wrapper of exclusivity and the subtle "only tell a few people".
Now my real questions is: was the real social experiment about getting people to smile on command or (the meta experiment) was it about observing the behavior of people being told of the smile idea and trying to spread it? Only Chris knows....