Real Estate sites using Product and Offer?

I've noticed several real estate listings sites, including one of the 
largest (Trulia.com) are marking up their property pages (the page 
dedicated to a single home for sale) as a Product, an Offer, or both.

Can someone explain to me the advantage of marking up a real estate 
listing as a Product or Offer, as opposed to using the Real Estate 
schema.org markup?

Does the use of Product/Offer allow you to use additional useful 
properties that Real Estate doesn't?

Any insight into why large, reputable companies may have come to that 
decision is appreciated.

Received on Tuesday, 27 December 2011 17:27:45 UTC