Facebook Timeline is a social media feature introduced by Facebook in September 2011 and rolled out to all users in February 2012. Timeline combines a user’s Facebook Wall and Profile into one page, creating a more visually holistic profile. It includes reverse-chronological details, by year, of a user’s Facebook history with key life points, including birthdays, weddings and other major events.

Timeline reorganizes all stored user information for display, rather than archival. In previous Facebook incarnations, it was more difficult or impossible to view outdated events, photos and comments. Excerpt from techopedia.com

Facebook Timeline was a radical new profile page design that Facebook launched around the end of September 2011. It was announced by Mark Zuckerberg at Facebook’s F8 conference following an introduction from SNL’s Andy Samberg.

Facebook Timeline changes the default profile from a list of your most recent updates to a complete summary of your entire life since birth. It includes photos, videos, status updates and locations you have visited. The new Facebook profile is divided into two main columns, with a line down the middle representing the passage of time. Users are encouraged to add life events which were not captured by Facebook, particularly those that occurred before the person joined Facebook.

Timeline uses an algorithm to assess the most important moments of your life, which can then be edited to your satisfaction. Unwanted updates can be hidden from the Timeline.

The new profile pages are thought to constitute one of Facebook’s most extreme redesigns so far, completely reimagining what a social networking profile can be. Timeline also means that Facebook now bears fewer similarities to Google+, a social network from Google which currently uses the standard format of showing the most recent updates first. Excerpt from mashable.com