WHO GETS THE LISTING DATA? | PLAIN LANGUAGE SERIES | PART 4 OF 5
Twelve Terms That Decide Who Sees Your Home
The vocabulary of the listing data fight, translated into plain language
By Saul Klein and John Reilly August 2026
Arguments about real estate data are conducted in a specialized vocabulary, and the vocabulary is doing real work. These terms decide who may see your home listing, who may build products from your sale price, and who pays whom for what. Here are the twelve that matter most, in plain language. This article stands alone as a reference; the definitions below are simplified for readability and are not the formal definitions in any rule.
MLS (Multiple Listing Service). The shared database of homes for sale that competing brokerages in a market build together. Everyone contributes listings; everyone receives everyone else’s.
Data feed. An automated, ongoing delivery of listing data from the MLS database to a company’s own systems, as opposed to looking listings up one at a time. Feeds power brokerage websites, apps, and internal tools. Most of the current fight is about who gets a feed and what they may do with it.
IDX (Internet Data Exchange). The long standing program under which brokers give each other blanket permission to advertise one another’s active listings on their public websites. It is why you can see every brokerage’s listings on any one brokerage’s site.
VOW (Virtual Office Website). A password protected brokerage website that works like an online office. Because you have registered as a client, a VOW may show you richer data than a public site, such as what homes actually sold for. A 2008 settlement between the Department of Justice and the National Association of REALTORS® guaranteed brokers the right to operate these.
Syndication. Sending listing data outward from the MLS to other websites, such as the big public portals. When your home appears on a portal, syndication put it there, and whether it goes out at all is the seller’s choice.
Back office feed. A data feed used inside a brokerage for internal work, pricing analyses, recruiting, accounting, rather than for public display.
Data license. The legal permission that defines what a company may do with the data it receives: display it, analyze it, build products from it, keep it, or none of the above. A feed is the pipe; the license is the permission. The same pipe can carry the same data under very different permissions.
Derivative work. Something new created from the data rather than a listing simply displayed: a home value estimate, a market report, an analytics product, an artificial intelligence model. Derivative works are where the money concentrates, and creating them from a copyrighted database requires permission.
Paper broker. A firm that holds a broker license, and therefore qualifies on paper for MLS membership and data access, but does not actually represent buyers and sellers. The license functions as a key to the data rather than a license to practice.
Grey market. Not outright theft, but the sprawl of listing data circulating in ways nobody quite licensed and nobody can quite trace: old feeds still running, data delivered for one purpose used for another, copies passed to companies no agreement ever named. The grey market grew out of decades of sending complete copies of the database and trusting recipients to follow the paperwork.
Non disclosure state. A state, such as Texas, where sold prices are not part of the public record. In those states the MLS is often the only reliable record of what homes actually sold for, which raises the stakes of controlling access to it.
Commercial data license. A negotiated contract, separate from MLS membership, under which the MLS grants defined data rights to a company for a fee. As the industry redraws its rules, more and more uses of listing data are moving from membership benefits to commercial licenses, which is really the whole story in five words: from benefit to priced contract.
This article stands on its own and is also part of the plain language series “Who Gets the Listing Data?”. Copyright 2026 Saul Klein and John Reilly. All rights reserved. Commentary and general information, not legal advice.
