This will be different from offer to offer and Im sure there are many ways to set it up, but I got some info about it so let me tell you what I know. Some time ago, I was building a website that we planned to monetize with real estate listings, so I was doing some research about the possibilities. I found several real estate portals that had affiliate programs, they would give you API to their DB and you could display the listings on your site for a commision (or cpc/cpm).
I also found many "local" realtors who were willing to pay for leads - customers interested in property in their areas. So the basic setup would be like : detect where the person comes from, find out what they are looking for... then match it with available real estate and show them the listings and forward the contact info to matching realtors. Next step is to match them with local mortage agencies/banks etc ...
We didnt finish the project in the end, but there is a lot to do here. I found plenty of sites that were willing to pay for exposure for their products or services that were related to real estate and moving in general.
Here are some links for you that you might want to take a look at for more information :
http://www.affilorama.com/blog/real-...liate-programs
http://www.highpayingaffiliateprogra...ate-affiliate/
http://www.zillow.com/affiliate/
http://www.affiliateguide.com/realestate.html
http://www.trulia.com/publishers/platform/
It's hard to know exactly what they are doing from the screenshot. But I'm guessing they monetize their traffic using a combination of co-reg and co-sponsor deals.
Fill out the form yourself with a valid throwaway email address and phone number and see what happens. You'll find out very quickly and first hand how they monetise, instead of needing to speculate on this.