Facebook lists four features for the new Timeline feature:
At the top of your Timeline, you have a link to view activity in your private Activity Log. It is a list of everything you’ve done or posted on Facebook and is only visible to you.
From your Activity Log, you can control which stories you want to feature and which ones you’d prefer to hide. You can also change the privacy beside each post or even delete it. To find a specific story or type of story, simply filter by content type or application. You will also find your pending posts here and can quickly approve new content tagged by your friends. Your Activity Log lets you go all the way back in time to your very first post on Facebook. You can relive old memories or delete things that no longer represent who you are.
Just as today, for every post there is an inline control beside it that shows you who can see it and gives you the option of changing it.
Apps are a big (optional) part of the Timeline. After you approve an app, whenever you take an action using the app, a story is seamlessly published to your Timeline.
Whenever you add an app to your Timeline, you can feature your favorite activities, such as listening to music, watching movies, or reading books.