Simply put, for the most part (with some exceptions), you control who sees your posts. Here's how - set all your privacy settings to "FRIENDS ONLY". It's really that simple.
Here's how you know if you've done it right: at the bottom right hand side of the status update box it will say "public", "friends", "only me" or "custom". If your overall privacy settings are set to "Friends" it will say "Friends".
|See the tick next to friends? That's what you want!|
Say I update my status, with privacy set to "friends". Friend #1 comments on it, her friends will see it in their ticker feed IF (and only if) they are also my friends.
The top post is set to public, if I comment on this post everyone and anyone can potentially see my comments - FBUser #10 friends and their friends (including my friends). The bottom post is set to friends only - the only people who will see my posts are FBUser #16's friends - not my friends, but FBUser #16's friends.
You might be looking at your ticker feed and seeing a whole bunch of names you don't know. Usually it goes "Friend commented on Stranger's post". Click that post and you will find that "Stranger's" post was set to public.
So, the upshot is:
- if you want the world to see your message, use the public setting (and be prepared to wear the consequences, both good and bad)
- if you just want to communicate with YOUR friends, use the friends setting.
At the beginning I said "with some exceptions". If my post is set to "friends", someone is tagged (either by me in the original or by a friend in their comments) my post is now shared with the tagged person's friends.
If I post and tag my husband - all of my friends AND all of his friends can see my post.
If I post and Friend#234 comments and tags their friend #45, all of my friends and all of #45's friends (even though I don't know them) can see my post. So, beware of who is being tagged in your comments!
(Note, my screenshots may not look exactly like yours. I use Social Fixer (https://www.facebook.com/Socialfixer) which is a wonderful browser add-on for removing some of the annoying features of FB.)