They use listings that they download from other places - the actual real estate professionals who actually list and sell real estate.
It is not in the interest of tru lia to manage the information, because they want you clicking and scrolling through their site to find things, and they hope to get your contact info and sell that too.
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if you are looking to purchase your best bet is to get your own buyers agent. This will not only help you narrow your search by eliminating properties that do not match your criteria thus saving you lots of time, but also your agent can give you the most updated information and best of all utilizing your own buyers agent is free to you. If you want a customized list of houses for sale that match what you are looking for email us your preferences and we'll send you the free report. email@example.com or firstname.lastname@example.org
If you are going to use a large national site, then realtor.com is your best bet. if you are serious about finding a home the best thing to do is connect with an agent that can set you up on their access to the MLS. This pulls directly from the Massachusetts MLS and should provide the most up to date information.