"Once timeline is activated on your profile, you have seven days to 'clean up' - and you will probably want to.
Things from your past that may have been previously hidden deep within your photos or timeline can be much more visible.
If there is anything particularly you don’t want shown, such as your relationship status from five years ago - which will be public by default - you’re best to click on the right hand side to the year it occurred, such as 2006, find the post and choose to either delete or hide it.
It all has to be done manually.
You can now choose directly from the right-hand side of nearly every section on profile who sees what for individual sections (such as photos, posts, likes etc). When you click on the item, you can choose whether it is seen publicly, by friends or by a customised list.
If you enable any timeline apps, be sure to read their privacy policies thoroughly - many will not ask again before posting information to your profile. Spotify, for instance, will default to filling your timeline with what you listen to, unless you tell it not to.
Facebook now has the ‘View profile as’ feature on the main page, rather than in privacy settings. This lets you check how different people can see your profile so you can then customize it as you wish."
A real pain, eh?