The company's technology, which lets users touch up and share photos taken with smartphone cameras, has caught on quickly, allowing Instagram to build a base of more than 15 million users in just two years.
But as with other mobile-focused start-ups, such as Foursquare Labs and Flipboard, its success in attracting users has yet to translate into significant revenue in the way it has for some desktop-oriented Internet companies, such as Facebook Inc. and Zynga Inc.