Basically, the MLS is like a virtual warehouse. I like to call it the “home depot” of homes. A MSL listing means property is available for sale, it goes on the MLS. When it is sold, it gets taken out of the MLS.
Since real estate cannot actually be stored in a warehouse, this means MLS only contains information. So the MLS is actually a database – an extremely convenient way to know what is available for sale at a given moment. That is why real estate agents developed the MLS.
Since developing and maintaining the MLS system wasn’t free, agents created local “MLS Associations,” required membership, and charged each other annual dues (plus additional fees) so that they could pay for the necessary staff and materials to make it work.
In the really olden days, an agent submitted listings to their local association and the MLS staff compiled the data on what was available for sale and what had been sold. Once a week MLS members received a book that showed all the current listings.