Some e-marketplaces already are on the decline. IndustrialVortex, a B-to-B for industrial automation products, ceased operations after failing to secure second-round financing. The 6-month-old exchange, which handled more than $20 million in RFQs in June, shut down with a terse message of regret to buyers and suppliers. Company officials declined comment.

BizBuyer.com, an exchange for small businesses, says it’s eliminating several product categories and refocusing on telecom services, office equipment and insurance. And Neoforma, a high-profile health care exchange, reports that it lost nearly $100 million in fiscal 2000. The company recently laid off 25 percent of its 340-person workforce; its stock last week traded at about $3.50, down from a high of more than $60.

Companies looking to join or just transact business over an e-marketplace must now determine which ones are most likely to survive and thrive. Some online exchanges, such as those that traffic in office supplies, require very little commitment. But most exchanges will demand that their participants revamp their online catalogs and tie in their back-end applications to unlock the potential for increasing sales and improving transaction efficiency.