Here's how Facebook works. You have a profile. Your friends (and maybe even people who aren't your friends, depending on your privacy settings) are able to view this profile. When you put information on your profile in a status update or link, this shows up in your friends' news feeds.
Sometimes in real life, you may encounter friends who know about things happening in your life because they saw it in their news feed. You are not allowed to be weirded out, offended, etc. by this because you chose to put this information on your profile.
I've been in slightly awkward situations in which a friend tried to tell me something and I stopped them with, "Oh yeah, I saw that on your Facebook." A friend of mine actually had a girl call him a creeper because he knew about something she had put on Facebook.
This is not rational. If you post something on Facebook, just go ahead and assume that pretty much every person on your friends list has seen it. If that makes you uncomfortable, either don't post it on Facebook or delete some friends.