Getting notifications for everything you do on FB
The "Close Friends" feature allows your current friends to keep uncomfortably close tabs on you. Every time a Close Friend does anything on Facebook -- likes or comments on a photo, updates their status, checks in somewhere, etc. -- you'll get a notification. But since Facebook doesn't tell people when they've been added as a Close Friend, there's no way of knowing who's getting an up-to-the-second broadcast of your online behavior.
To add a Close Friend, go to their profile, click on the "Friends" drop-down menu next to their name, and select "Close Friends." Just don't make it weird, OK?