I don't think this analogy works, given the significant differences between investing and product adoption. Just because a product has become mainstream doesn't indicate that the "end is near." In fact, I would argue the contrary, particular in this case. There are significant network effects in social networking. As the number of Facebook users increases, the value of Facebook to existing users (those already on the network) increases. Now, not only can I use Facebook to communicate with my college and grad-school friends, but I can use Facebook to stay in touch with my extended family, more distant friends, acquaintances, etc. If I want to maintain these relationships, I'm forced to either stick with Facebook, or rebuild my social network elsewhere. If I wanted to rebuild my network elsewhere, I would have to convince most of my social network to defect to the new service, otherwise the new service is of little value. Facebook's recent moves around privacy (and changes in functionality) are clearly unnerving its customers; however, this alone won't cause the collapse of the service.