Google has just released a new open source web API that allows developers to create interactive 3D applications in the browser. O3D, which runs on both Windows and Mac (and even Linux with some tweaking), is provided as a plugin that will run on most popular browsers such as Firefox, Safari, Google Chrome, and Internet Explorer (more details at our Google O3D API Profile).
The Google Code Blog announced the release of O3D:
This is certainly an interesting new API for developers interested in engaging users with a rich way of visualizing content and data. We're looking forward to seeing how O3D will evolve, given its status as an open source project, and we're excited to see the creative and meaningful ways in which developers will leverage this API. Note that a new O3D blog has also launched as well.