A Web site is a Web site, right? Once your site is up and working, there isn't much that can go wrong. Or is there? What if performance of the site itself-that is, the speed with which people are able to access it and get the information they want-makes your customers feel more like they're on the World Wide Wait? How do you know if your Web site is performing as well or better than the sites of your competitors? "The pilot of a 747 can't sense all of what's going on with the aircraft," says Umang Gupta, chairman and CEO of Keynote Systems Inc., a San Mateo, Calif., firm that monitors Web site performance. "On the Internet, when you are working with a scale of tens of thousands of people, millions of pages, and similar numbers of transactions, you have no way of knowing if you are doing a good job or a bad job without having metrics." Among the companies and organizations that use Keynote's Web site monitoring service are Dell Computer Corp., Network Appliance Inc., General Motors Corp., Samsung Electronics Co. Ltd., and AAA Michigan. "Before we got Keynote, we had no way to measure our site's performance," says Mitchell Kim, e-commerce and Internet consultant at Samsung Data Systems America, Piscataway, N.J. AAA Michigan uses Keynote's error-based alarm functions, which provide the auto service with instant pager or e-mail notification of Web site problems or bottlenecks that slow down or prevent users from accessing the site. That way, AAA Michigan managers can take steps to fix the problem and minimize downtime for the site. "The online market is highly competitive, and the better our Web site performs, the more likely we are to keep a customer online and keep his or her interest in our products," says Rick Semack, e-commerce manager. Last spring, Keynote augmented its service by integrating it with Agilent Technologies Inc.'s Firehunter data obtained from inside the client's network firewall. Firehunter, which is used by Qwest Communications International Inc., U.S. Internetworking Inc., and BMW AG, monitors e-commerce sites, providing the equivalent of a stock ticker showing what's happening in real-time. "Perhaps it's taking longer for customers to find the preferred product on your site," says Scott Thull, strategic alliance manager for Agilent's Firehunter business unit in Fort Collins, Colo. "Or a sales manager can see how many people are using the site, so that data on sales are not a surprise at the end of the day. We believe that sooner or later, companies are going to figure out the importance of performance of their e-commerce sites."