I'm obviously not just thinking of buying a property in the US but I'm also selling property in Australia. In doing this, I've scoured all the websites I can find, that carry out listings in both regions.
Seriously, if you're in the real estate business and you're not making use of mapping technology at all, you may as well call it a day. It's the same as not having a product listing gallery or a shopping cart in an e-commerce site.
It doesn't necessarily end with "look this is where the house is" it's more to do with "look this is where the house is, here are some others around it too".
I've gotten into the habit of expecting this to occur as I know my current location really well, but I know little about my destination. So I'm looking for visual queue to make this process easier for me, in return I'll happily contact whom ever you put in either the form or phone details within the house I click on.
A lot of sites do this today. If you know a company that's not, encourage them to do so!
This is now even more critical with economies around the world going through some stabilisation pains, folks are either looking to sell or buy and are more interested in figuring out financial benchmarks more so than ever and virtual maps are the perfect starting point to visually representing this.
Bronwen and John from Soul Solutions (two friends & MVP's) have done a lot in this space, ask them for the heads up on all this mapping buzz - should you not have caught it yet.