For Sale By Owner - FSBO
Pronounced "fizzbeau," this event is the nightmare of realtors far and wide. It happens when an owner lists her home for sale without any selling agent (commission-getter) attached. Sometimes it works and the owner saves the commish; sometimes it doesn't, and the fizzbo has to list their home with a real agency.
Beware the new Zillow products if you're a realtor. They're coming for you.