How to Change the Facebook Share Setting for Previously Shared Content
Hopefully, you know how to set your default privacy for Facebook status updates and photos, and know that you can set the privacy individually for each status update you share. When you set your privacy to public, you're essentially allowing anyone on Facebook to see your update — but only friends can comment on those updates, with the following exceptions:
If you post a status update that tags someone, anyone who is friends with the person you tagged can comment on your status update — even if you’re not friends with them.
If you turn on the Follow option for your Facebook account, anyone who follows your updates can see and comment on any public updates.
On a related note, when Facebook released the timeline version of personal profiles, your updates from previous months and years became more readily available. This may or may not be a problem for you, depending on what you’ve shared over the years.
Luckily, Facebook recognized the issue and included a way for you to change the share setting for individual pieces of content. As you set up your timeline, you may choose to customize how you share certain things. To change the share setting for previously shared content, follow these instructions:
Visit your personal timeline and click the Activity Log button directly below your cover photo.
Your Activity Log page appears.
Find the status update for which you want to change the sharing preference.
If you hover your cursor over the share icon (two silhouettes, a globe, a lock, or a gear, depending on your current settings), you can see the original share setting for a status update.
Click the share icon and choose a sharing option from the list.