Seventy-nine percent of home sales in golf course communities are closed without help from an outside real-estate sales professional, says a survey by PrivateCommunities.com.

Most are sold by in-house sales representatives for the developer and never make it to the local Multiple Listing Service. In fact, the poll finds that slightly more than one-quarter of a golf community's sales staff do not belong to the National Association of Realtors.

According to PrivateCommunities.com President Elisabeth Miller-Fox, "Golf course homes for sale behind the gates are largely invisible to the general public."

The company hopes to change that with the addition of golf properties to the vacation homes and master-planned retirement communities already listed on the site. PrivateCommunities.com allows second-home buyers to search the listings by location, price, and features; and it provides detailed floor plans and virtual tours.