I hope this doesn't touch off some sort of multiple listing service data-purity war. But I think it's worth digging into this WordPress plug-in a bit.
It's named, in a very search-engine-optimized way, "The WordPress Real Estate Plug-in." It's designed to add property-search and lead-gathering capabilities to a WordPress site.
The plug-in is developed by the people at Go Smart Solutions and released under the GNU General Public License. (Keep reading to learn more about what that part means and why it's important.)