Facebook expanded its Graph Search to include posts and status updates. Users should check their privacy settings if they want to limit the people who can search every post or status update they have ever made. The most important thing you can do is to check your privacy settings often, especially after new features are released. Check your Activity Log and remove tags from photos and posts you’re tagged with that you don’t want to be searchable, or use hashtags to keep strangers out of your conversations and unaware of your activity.
Source: https://thehackernews.com/2013/10/Facebook-Graph-Search-Privacy.html