The Internet already swirls with millions of images created by consumers using digital cameras. And by the end of 2004, some 180 million cell phones worldwide will have cameras built in, according to InfoTrends/CAP Ventures, an analysis firm in Weymouth, MA. So it's not surprising that one of the fastest-growing Internet applications is online photo sharing: the creation of individual or group Web albums where people can upload digital snapshots and invite friends to view and comment on them or order prints.

Not only is it becoming one of the hottest uses of the Web, but it's also driving a booming business in the sale of website memberships and photo prints. Compared to overall e-commerce revenues, which reached some $54.9 billion last year, earnings at commercial photo-sharing sites in North America are still small, totaling $124 million in the same period; but they're set to increase to $206 million this year, says Jill Aldort, a senior research analyst at InfoTrends. And several companies, including Microsoft, are introducing technologies intended to turn photo sharing into the basis for supercharged social-computing experiences, meaning everything from photo-enhanced instant messaging to community organizing and networking.