Chris MacAskill of the photo-sharing site SmugMug says that when the company was started by his son Don, everyone thought the market opportunity would be in sharing photos online.
But while the company's subscription has grown to 100,000 paying customers, the fastest-growing part of the business is photo prints.
"When they see them on the screen, they like printing them out," MacAskill says. "We were wrong about that."
A lot of other entrepreneurs would like to be that wrong -- SmugMug has been profitable since 2005.
Internet users like high-quality prints like those found in photo books, and the company is now selling those made by consumers using services from Blurb, the online publishing service we've covered extensively here.