When two people with the same name on FaceBook "friend" each other then swap profile pictures.
Each "friend" assumes the identity of the other, and updates their home pages as if they were the other person, creating a quantum entanglement of their separate identities.
Hey! I found another guy with my name on FaceBook. For April Fools Day, we did a FaceOff and confused everyone! It was great!
Somehow, he ended up with a date with my sister.