One dev said that "Given the advanced functions in the DSi, such as the microphone and camera, the company told us that there are a variety of opportunities for a variety of apps, both in a games sense and a non-games sense, that we could offer."
Nintendo of Japan already has a few non-game apps on the DSi Shop, including Nintendo-themed calculators, two clocks, and a travel guide. The rest of the service consists of small games, many of which are miniature versions of existing DS games. It seems that Nintendo's western branches have the same kind of thing in mind for third-party DSiWare offerings. We'll most likely find out next week, when Nintendo will present two talks at GDC: one about the DSi's design, and the other from Satoru Iwata called "Discovering New Development Opportunities."