The actual XML that is pushed to the web for crawling and indexing could be generated any number of ways and implemented in any number of systems. The trick is using a standardized XML-based vocabulary to make the listings interoperable with each other. The system generates both an XML page and an HTML 3.0 Web page for each listing as it is entered. The OpenMLS product immediately provides a real estate office with a World Wide Web presence for every listing. If a listing is modified, new XML and HTML documents automatically replace the outdated pages.
Consumers view pages on the web with the most current information available.
The OpenMLS server uses DTDs to validate the listings entered by the listing agents. Using a DTD to associate a particular vertical market's meaning to a document's content turned out to be a tricky business indeed. In developing the DTD, I had to determine the common denominator for the various MLS forms across the country. I feel that the path to standardization in the real estate industry will be taken with small steps. If the proposed standards are too precise or restrictive, there will be too many points of contention.