I have always thought that FaceBook was the most abstract and poorly designed out of all the major social networks. The current fascination with FaceBook has obviously eluded me.
Princeton Researchers: Facebook Epidemic Headed For Collapse
This is an interesting comment about the lifespan for social networks:
The paper said that adoption of social networks is “analogous to infection,” and abandonment of social networks “is analogous to recovery” from a disease.