The practice of luring friends (Facebook Sharks), by throwing "chum" into the water. Chum usually consists of political or religious comments... far too tempting for a Shark to ignore. The water in this case would be status updates and walls.
Related to:
Facebook Shark:
A fiercely opionated friend with a voracious appetite for debate. Someone who will pounce on loose comments and opinions and attack without mercy.
When someone knows a Facebook Shark is around... Facebook Chumming would be making a comment like:
"The Church isn't interested in money or power...."