People can add pre-Facebook memories, too. The Timeline goes back as far as the user's birth date. The Timeline is blank for now, but Facebook hopes people will fill it up by scanning old photos and adding dates and places of life events. It's even possible to add a status update from 1984 - two decades before Facebook's 2004 debut.
For many users, turning on Timeline will likely serve as a trip down memory lane as they rediscover photos and updates they shared weeks, months and even years ago. It may also prove to be a helpful reminder about just what they've posted on Facebook over the years. Youthful indiscretions, unfortunate photos and hasty status updates can be hidden from Timeline or deleted forever.
Facebook has rolled out Timeline to small groups of users over the past few months. It's available to everyone else starting Thursday. To find it, search for "timeline" on Facebook. Click on "Introducing Timeline." There, you will find a link to get it.
Once you do this, though, you'll have only a week to move stuff around, hide photos or feature them more prominently on your page. After that, Timeline will replace your old profile page, though you can change things on it at any time.
The privacy settings for Timeline are no different from your existing privacy settings. But it's very likely that the posts you shared with friends three years ago are now shared with a much larger group of people, as you've added new friends, co-workers and acquaintances.
And what of the sad memories? Facebook's introductory video of Timeline is full of smiling faces and happy babies. But as users curate their life events, there may be moments they won't want to immortalize on Facebook.
Death, illness, divorce - will these be missing from your Timeline?