There's even a way to undo your past public transgressions
Facebook is making all of the public posts on the social network easily searchable. The idea is to make it easier for people to follow conversations unfolding in real time, like on Twitter. But, luckily for those who don’t want to have their every thought be a contribution to the public town square, there’s an out. Just follow these steps:
On your News Feed page, click the lock symbol in the top right corner of the screen, next to the globe icon that denotes notifications
Below the big purple dinosaur that pops up, click the question “Who can see my stuff?”
You’ll have three options for this setting. “Only Me,” means the posts are fully private, only viewable to you. “Friends” means your Facebook friends can see what you post and search for your posts. “Public” means anyone on or off Facebook can see your posts, and anyone with a Facebook account can search your posts.
You can also change this setting easily on a post-by-post basis. Below the composition box and to the left of the big blue “Post” button on any post, you’ll see your current privacy setting. Here you can change it to “Public,” “Friends,” or “Only Me” as needed.
Note that these changes will only affect future posts you make. If you realize you’ve been inadvertently airing your political views to the entire world and not just your high school acquaintances, you can change the “Public” setting of older posts through a simple process:
Click the lock in the top-right corner of News Feed page
Click “See More Settings” at bottom of pop-up menu
Click “Limit Past Posts”
Facebook will show you a warning about how this is going to change all your posts that you’ve shared with friends of friends or with the entire public to being viewable only by Friends. Take a deep breath and click “Limit Old Posts”
By Victor Luckerson for Time Magazine