While the Securities and Exchange Commission investigates the bandwidth trading practices of Enron, Global Crossing and others, fiber links are quietly changing hands elsewhere with help from an Internet-based matchmaker called Fiberloops (www.fiberloops.com).What fiber glut? Many carriers would sell dark fiber links if they could find a buyer. Other carriers would expand their network if they could learn who had links in their target market. Now they can connect online.The site, run by Boston Internet company CDS Business Mapping, compiles data on the location and ownership of lighted and dark fiber in both local and long-distance markets. Additional information includes available conduit, co-location facilities and telecom real estate.Of course, this information is available elsewhere for those individuals who are willing to comb through public records, utility maps and company assets. The Web site, however, enables visitors to search data by geographical area for site and fiber details, contact information and interactive maps."Our goal is to track everywhere that people have fiber in the ground," said Dan Munson, the company's vice president of sales and marketing. "We make it so that if someone says I need to get from here to here, then they can do that with a minimum of work."The company facilitates the trading rather than engaging in it. It draws a 3 percent commission from any completed deals it brokers. In February, the firm added 25 companies to its database, raising the total number to 60, representing more than 260,000 route miles in more than 250 cities nationwide.Most of the activity, Munson said, is in buying and selling dark fiber -- largely in local markets."We see a lot more lit fiber on the long-haul circuits," he said. "But most carriers want to buy dark fiber. It's paid for up-front and then the carrier controls it end to end."But activity is a relative term. There is not a lot of money changing hands, Munson said, even in dark-fiber transactions. Neither do purchases of dark fiber guarantee commensurate purchases of laser and detector components to activate the link. A carrier who purchases 12 strands of fiber may light only two of them and reserve the remaining 10 for future growth.For Fiberloops, which launched its Web site in September 2000, the market slump has been a double-edged sword. Although business is slower than it might have been, the company is better positioned to attract new clients.