The are new 3D Web engines coming up like mushrooms after a warm rain. I can point out the following ones: 3DMLW, Virtools, WireFusion and Vivaty. Why aren't Flash10 or any Flash based APIs in this list? Because Flash 10 isn't really a 3D engine and the APIs are usually slow and too big. The most interesting from this list is probably 3DMLW because of being open source, having a nice open community and trying to do things in a different way than the others. They have reached version 1.0.1 and are probably a little bit behind the others in functionality but gaining fast. Also a free editor for 3DMLW named Quantum Hog is in beta stage and up for downloading.