Many of the heavily trafficked Web sites offer free e-mail along with their regular complement of content and services. Yahoo!, for example, offers news, weather, stock quotes, maps, classified ads, and other content aside from its actual search tool. But in building a business model that features a suite of Web "utilities" designed to keep users coming back again and again, Internet sites such as AltaVista, Pathfinder and Yahoo! might also find themselves with new support challenges, according to analysts. "It's a commodity, and a tit-for-tat kind of thing," said Patrick Keane, an analyst with Jupiter Communications. "If one of them has it, all of them have to have it. They need it to retain users and increase their ad revenue." Analysts also caution that as these Web sites add more bells and whistles, they face potential risks when those services aren't available. Glitches frequently occur with free e-mail services. Tuesday morning, for example, Microsoft's Hotmail service, with 11 million accounts, was widely unavailable over the Web for about two hours. Hotmail has been under close scrutiny by users since its purchase by Microsoft Corp. Dec. 31, and the service glitch-which Hotmail said did not originate with its servers, and might have been a problem with its service provider's network-is not likely to improve its image among users. "E-mail is crucial for users, and they're very sensitive about it," said Jupiter's Keane. "It's much more important to users than Web access ... and, obviously, if you can't get access to your e-mail you're going to be perturbed." Keane and other analysts say they do not believe Hotmail's service is slipping, however, chalking any glitches up to inevitable "speed bumps" associated with Hotmail's integration into Microsoft and its Microsoft Network online service. AltaVista's move also marks its continuing, and late, transformation into a more commercial service, analysts said. AltaVista has traditionally disdained extras such as news and weather in favor of focusing on its search technology, but lately it has added such services as Web-page language translations. "They have to move toward the model of the other services to survive," said Jupiter's Keane. "It's inevitable."