Camptocamp, in collaboration with the School for Architecture, Engineering and Geomatics at the University of Northwestern Switzerland, have launched OpenWebGlobe: http://swiss3d.openwebglobe.org/.
This is a true 3D open source virtual globe using the latest web technologies: WebGL and Google’s Closure compiler. No plugins are required for modern browsers, and Internet Explorer users need only install the Chrome Frame plugin.

A full HTML5 WebGL virtual globe
Zoom into Switzerland and you’ll find detailed orthophotos of Switzerland from Swisstopo’s SWISSIMAGE data set draped over Swisstopo’s rich DHM25 terrain data set. OpenWebGlobe uses a Triangular Irregular Network model that offers both accurate representation and is low bandwidth.

Fine grained aerial imagery and TIN elevation for high quality rendering
Under the hood, the Javascript client uses a streaming chunked level of detail algorithm to request only the data that is required for the current view. Detailed models of close objects are loaded, whereas only simplified models of distance objects are requested. This minimises the data streamed to the client while still allowing the user to explore the data in full detail.
Demonstration textured buildings were converted from the industry-standard Collada format and optimised for the web.

EPFL textured buildings using Collada and OGC KML

Swissborders displayed as an OGC WMS overlay layer
Behind the scenes, the application is hosted entirely in the cloud. 60 million image and elevation data tiles are hosted in on Amazon S3, and the application itself is served from load-balanced, redundant EC2 instances, all managed by Camptocamp.
https://github.com/OpenWebGlobe/WebViewer