Real estate site has all kinds of info - Do-it-yourself feature allows users to add data they want

[ordersup]

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2007/07/17/BUGOSR1F1H1.DTL&type=tech

[Tichy]

I have also been interested in creating a mashup about renting and buying houses, on a smaller scale, though (basically because I also need it for myself).

I wonder about the legalities of creating mashups, though - is it legal to just pull information from Craigslist and other pages? I wouldn't mind forwarding my users to the pages I pulled the information from for closing the deal, but it still seems difficult legally.

[ordersup → Tichy]

well, if they offer the api or rss feeds like CL does... i don't see why not. :) http://www.housingmaps.com/ does it :)