October 3, 2014: We are proposing an extension to the Open Graph protocol to allow for easy sharing of 3D objects as "rich objects" that is on par with the existing video, audio, book, song, and album Open Graph object types. This proposal has the support of the following companies in the online 3D space: Clara.io (us!), Verold.com, Sketchfab.com, 3Dshap.es, Yobi3D.com and Pinshape.com.
We run Clara.io, a popular online 3D modeling & rendering webapp built upon Three.JS. Lately, we added a large publicly accessible library of free 3D models created by our users, for our users. This has proved to be very popular.