Check out these Zillow widgets and decide whether you can benefit from these.
In general, these widgets are provided free for you so that you can add content to your web sites without having to spend time and money to own and keep these data accurate and updated. These contents, if properly used, can attract more visitors to your site which in turn can help increase sale!
As demonstrated here, there are options to keep visitors from going to Zillow if you create those capabilities for your site. This will require advanced programming though.
I also have a similar demo for TRULIA widgets.
I don't endorse any of these. I just play with popular technology and try to demonstrate it to others in my spare time.
If you have any suggestion for reviewing new technology, feel free to contact me.