Final answer:
A 'blind ad' is an advertisement that omits the name of the brokerage representing the seller, often discouraged or prohibited in real estate to maintain transparency.
Step-by-step explanation:
An ad that does not state the name of the brokerage representing the seller is called a blind ad. Blind ads are generally discouraged or even prohibited in real estate because they can be misleading and fail to provide necessary information to consumers. The requirement to include brokerage information helps ensure transparency and accountability in the transaction process.