It doesn’t look like Buddypress would be the most suitable script to develop a site like that. Zillow is an interface on a bunch of databases for homes, agents, lenders, etc. You’d have to adapt the users and post tables in WordPress, which aren’t very flexible…, or develop something around it.
Are there any open source PHP scripts more suitable for this kind of site? Can’t think of any.
Are you asking whether a realtor community, storing and fetching realtor information is possible with BP? Or are you asking whether you could have that layout with additional member field data?
I agree with Peter in that, the data displayed here is coming out of a complex realty system. But the layout is nothing special. You could do that with BP. You’d just add the extra fields to the member directory layout (user meta) and the members themselves would have to supply that data in their profiles.
