Quirks, tricks and tips about using Facebook
1. Sharing friends' photos does not behave as expected
When a friend has posted a photo with privacy restricted to "friends only", and you share that picture with your friends or with everyone, this "sharing" is only visible to the mutual friends of you and the original poster. In other words, your friends will not see it if they are not friends with the original poster. The privacy icon that Facebook displays is misleading in this case. You can circumvent this by downloading the photo and posting it yourself, taking care of copyright issues of course. Sharing of links does work as expected. This quirk only applies to the sharing of friends' photos, uploaded videos, and status updates.
2. Close friends list
You have a "close friends" list. You will see every posting, every comment and every "like" of the people you have added to your close friends list, when you click on the "close friends" link in the left menu, as long as these comments and likes have been made on public posts or on posts of mutual friends.
3. Targeting information to specific people, openly or stealthily
You can limit the visibility of postings to one or more specific people using "custom" privacy, but these people will see each other's names, and they will be aware that they have been targeted. You can also limit the visibility of external "likes", external "recommends" and other activities on external sites, to one or more specific people, using the settings in your "activity log". In this case, the targeted people will not see each other's names nor will they be aware of the fact that they have been specifically targeted, because no privacy icon is displayed with likes and recommends.