From danah boyd:

Carmen is engaging in social steganography. She’s hiding information in plain sight, creating a message that can be read in one way by those who aren’t in the know and read differently by those who are. She’s communicating to different audiences simultaneously, relying on specific cultural awareness to provide the right interpretive lens. While she’s focused primarily on separating her mother from her friends, her message is also meaningless to broader audiences who have no idea that she had just broken up with her boyfriend.