"These kinds of listings are different from those on multiple-listing services, where agents may feel as though they have less at stake."

"People joined just for access to our multiple-listing service," he said.

Through this network, an agent in one part of the country could gain access to multiple-listing services in other regions.

Moreover, other members of a multiple-listing service will not accept a property while the current listing agreement is still in dispute.

Web sites like Homegain can display nearly the entire range of listings available to agents through the multiple-listing services.

Instead, they are reaching toward something that homeowners elsewhere in the nation take for granted - a multiple-listing service.

The free market as it exists today in Manhattan, however, is far less efficient than a typical multiple-listing service.

"It would be the same with a multiple-listing service in Manhattan," she said.

Sales of single-family homes are reported by local realty boards, based on numbers from their multiple-listing services.

When using a broker, make sure the house is included in the local multiple-listing service for maximum exposure and to encourage multiple bids.