What does a cracking electrical sound indicate in a light bulb socket?

#Shorts
The power flows intermittently if the switch no longer makes good contact between the two terminals when the light is turned on. The current may arc, which creates the crackling or hissing sound you hear and may cause excess heat (see video of discolored - brown - plastic). If you hear these sounds or if you hear a loud pop from a light switch or bulb socket, it's time to replace it!