If buying a home is all about location, location, location, then selling a home is all about listing, listing, listing. Online photos and write-ups are often the first things buyers see and read ...

Real estate listings are supposed to give you accurate information. But sometimes the agents behind the listing are just guessing—or being deceptive.

Zillow and Redfin are taking aim at listings for homes that have been publicly marketed prior to being entered into the MLS, taking steps to bar them from their respective platforms.