Most IDX systems used on real estate websites offer zero SEO Juice!Why? IDX systems have been designed to be integrated into websites via an "iframe" html command which basically means that your site acts like a "wrapper" so the IDX system appears to be operating on your site but in reality (and technically) it's not.
In this scenario none of the data in the IDX system, meaning the listing detail pages, photos, etc.
are search engine indexable - basically all that data is invisible to the search engines.
  RSS your IDX for some good SEO!How? First, your IDX system has to be able to produce an RSS feed of MLS listing data.
Second, your CMS needs to be able to read the RSS feed and render it into site content (blog post or article).
I know of at least two big open source CMS's (Joomla! & Wordpress) that have this capability and more and more IDX providers are offering an RSS feed ability as well.
Note: Some IDX providers offer this ability and other similar abilities but only if you use their CMS system (not always a good idea) so if you're in the market for a new IDX system, real estate SEO servivces or a new website be sure to ask specifically about this ability (not to be confused with simply reading rss news feeds).
Specific Benefits:

• Adds hundreds of pages of keyword rich content & images to your site
• Automates the content creation process 
• Leverages powerful SEO juice bottled up in your MLS/IDX system
• Dishes up lots of tasty morsels for the search engines
• Proven solution for creating and sustaining page 1 organic search results