1. follow steps
2. troll friends
3. ?????
4. profit!
2. troll friends
3. ?????
4. profit!
STEP 1: Write a Facebook status belittling one of your friends. Tag them in the status.
STEP 2: Before you post it, click the lock next to Share, and select "custom edit".
STEP 3: Set the post so that it will be visible to "friends of friends".
STEP 4: In the field "These people", pick the friend you've just tagged.
WHAT THIS DOES: You've just tagged your friend in a post that they can't read. It will show up on your profile page, and — more insidiously — it will show up on THEIR profile page. All of your friend's friends can read it, but your friend can't see.
Because they can't view the post, they aren't able to untag themselves from it. They can't delete the post, either. This means you can effectively flood friends' walls with anything you want to show up there, and your friends are powerless to stop you. They probably won't even realize what you're doing; they'll assume you posted and then took your post down.
I can't think of the most diabolical way to take advantage of this. But I imagine some of you can think of something.