Are you a real estate buyer, seller or real estate agent trying to  buy or sell a home? Surely you're familiar with the MLS (Multiple  Listing Service), a multitude of databases in each city of homes for  sale under the control of real estate agents. These databases all feed  into various website such as Realtor.com and Zillow.com to show home  shoppers what they are trying to sell.
Chances are you have not  heard of the BLS (Buyers Listing Service), a few have come and gone but  now a better version has been introduced. A BLS is a database of home  buyers requesting specific types of homes in specific neighborhoods  throughout America.
Whether you're a buyer, seller or real estate  agent, here is some help in deciding which one to use to help you buy or  sell a home. Pay careful attention as each has their advantages and  disadvantages.
Home Buyers & Their Real Estate Agents: If you  want to buy a home you have two approaches available. You can look at  the MLS (Realtor.com, Zillow.com, etc) to see about 5% of the homes in  any given neighborhood where the owner has hired a real estate agent to  display their home for sale.
The advantages of the MLS are: 1. Most likely a motivated seller.  2. Easy access to data and photos of the home.
The  disadvantages of the MLS are: 1. Buyers only see about 5% of the homes  in the neighborhood, less in better neighborhoods.  2. The seller's real  estate agent may already have a buyer waiting for this home.  3.  Seller's agent is already working with an agent friend that has a buyer.   4. Having to monitor the MLS daily waiting for a matching home to show  up.  5. Reactive approach as new listing trickle on to MLS.
Home  buyers using a BLS, where they post a request for the type of home they  want in a specific neighborhood have these advantages:  1. Access to  100% of the homes in every neighborhood.  2. Opportunity to buy a home  before it shows up in the MLS.  3. Seller's agents will contact you with  matching homes they have in the MLS (so you don't have to search the  MLS everyday for new listings).  4. Finding homes that are a better  match to your requirements.  5. Proactive approach to reach every home  owner in the neighborhood.  6. If you're a real estate agent working on  behalf of a buyer, this is the only way you will ever be able to "double  end" a commission.
There are a lot of home owners that would love  to sell their home if they knew there was a buyer already lined up to  buy the home. A lot of home owners do not want to have their home listed  in the MLS, have a for sale sign in the yard, open houses, etc. A BLS  enables a home owner so sell their home more discretely and privately.
Home Sellers:
If  you're a home seller, you could hire a real estate agent to input your  home in the local MLS system then wait and hope for a buyer to see it  and contact your agent. This traditional method will work eventually if  you wait long enough and are willing to lower your asking price over  time. Before you use the wait and hope approach, you and should look for  a buyers posting on a BLS that are a match for your home. You can  communicate directly with the home buyer (or their agent) and not have  to publicly display your homes information (photos, size, etc) to the  whole world.