The social timeline is a classic feature of the Facebook site that gave visual view of how the person made friends from over time. The social timeline will chart how each person meet the person and the length the person known the person. While editing friends on the friends list, a person can determine how they meet and how long ago, and it was ask for confirmation. If they event was confirmed, it was part of the social timline.
The social timeline was taken off the site in 2008 because of the rising popularity of the site and the confusion of the number of people on the friends list. A lot of people had acquaintances they meet on Facebook and faux events took place, making the social timeline no more.
Many groups were created to bring back the social timeline and some application developers were trying to build a social timeline.