At it's most basic, the BrokerIDXsites.com Brokerage Management and Real Estate Website System with Integrated Indexable IDX/MLS is a hosted top level domain website with IDX/MLS listings fully indexable and fully integrated on your domain - no iFrames or links to other websites.
"Free IDX" really isn't. Are you using a 'plug in" IDX solution or perhaps a free framed solution from your MLS or Board? Ever wonder why they give it away for free? Because in most cases, it promotes THEM, not you. Your website just becomes yet another inbound link to your MLS or Boards' website. A search engine sees this also - a search engine "bot" would see you, a real estate professional in your local market area, sending visitors to YOUR website to some other website to see listings. So why does the search engine need to index your website at all?