# product category URIs
http://en.wikipedia.org/wiki/Real_estate
http://www.dmoz.org/Business/Real_Estate/
http://wordnetweb.princeton.edu/perl/webwn3.0?s=real+estate
http://en.wikipedia.org/wiki/Retail
http://www.dmoz.org/Business/Retail_Trade/
http://wordnetweb.princeton.edu/perl/webwn3.0?s=retail