Netvibes API

From their site: UWA (Universal Widget API) is the next generation of the Netvibes wigdet API, the successor of the Netvibes Mini Module API. With this new release, our API becomes a powerful framework for Web widgets development - not only for Netvibes widgets, but also for many other environments, among which are Apple�s Dashboard and the Google Homepage. With the UWA, you only need one API to build widgets for a host of environments.