Clearly, Google still has serious issues on how they handle subdomains when delivering search results.
Try a search for Religious Jewelry as Art for example. You’ll find that IAF.net litters the SERP’s. They start with a result on page 2, then 3 results on page 3. After that, page after page after page of listings that contain nothing more than yellow page listings.
Personally, I think this speak volumes as to whether or not Google gives subdomains preference when delivering “relevant results” and their inability to handle them properly.
Google, could you please explain to me how, out of the first 210 results you deliver for a search for Religious Jewelry as Art, 181 yellow page listings from IAF.net is relevant to the searcher?