A study by Facebook belies the idea that social networks grow through what has been known as “viral” connections. What appears to be happening is that different groups like to be exposed through a network node, as in, you. If a number of like-minded people like the same thing, it isn’t nearly as powerful as a number of different people liking the same thing. That, however, seems intuitive to me rather than revolutionary, because anything that crosses over groups will be inherently more popular that something that is of interest to only a small audience. Family film, for instance, that appeal to a wider audience (say Romantic Comedy and/or adventure movie fans) will do much better than a family film that only appeals to families with children under 12.
This, to me, enhances the idea of serendipity because the network is more resilient in passing along information and having that information absorbed if the network is diverse. This reinforces the ideas I put forth in the original paper on the Serendipity Economy, in particular, that one must actively engage a network in order for serendipity to occur. The passing collection of, or connecting to, people in a social network is insufficient to drive serendipity.
For more on the Facebook study see New Scientist,
Variety, not viral spread, is key to Facebook growth April 2012 by Jim Giles