With Timeline, every status update, wall post and photo ever posted since the day you joined Facebook becomes easily searchable to you and your friends. For many--early adopters especially--dredging up the past for all to see can be a privacy nightmare.
When your Facebook account is migrated to the new Timeline--which Facebook started rolling out today--you'll have one week to make any adjustments to your past posts and privacy settings before your Timeline will go live for everyone to see. You can publish it yourself anytime within the five-day waiting period.
Here are what your options are for adjusting your settings, based on the level of privacy you want to achieve.
It's possible that your past posts have varied privacy settings based on when they were posted. One way--the easiest of them all--is to use one of the blanket privacy settings introduced not long ago: "Limit the Audience for past Posts."