So far, the evolution of social networks has been through three generations:
1G - Profile centric
The early social networks like friendster and myspace in 2005 emphasized user profile construction and sharing. The social graph is also part of the profile. Today, LinkedIn is still profile centric. A profile presents a user's static identity only. The persona presented is not yet a living creature, but quite useful when user wants to check out a new friend or contact.
2G - Activity centric
Users proactive interactions make persona live. In myspace, only the user comment area (message board) is the primary social interaction place, while the whole purpose of Facebook is to enable all sorts of social activities. After Facebook opened up its social platform, thousands of 3rd party social widgets flood in, making Facebook more activity centric. Activities keep users busy but may overload the users as well.
3G - Behavior centric
User's social behavior observed by others, mainly through passive or unintentional social message, is the trend of next generation of social networks. This is because behavior centric is more close to real life social interactions. One example is the body language in physical world. The behavior observation mechanism can be traced back to Facebook's innovative mini-feed and later beacon feature. The biological human can process the surrounding social messages efficiently. However, beacon as of today is extremely inefficient. Intelligent agents must be applied to partially automate the behavior observation. The recommendation or taste engines at Flixter, Amazon, Netflix, etc. are automated, though narrow banded to taste comparison only.
