It's not meant for web designing. You can create 3d images with it for your website but creating a website - code and all - is not doable. It's meant for 3d modeling for video, film, games etc.
These days all the video games whether the versions are online or offline are created in 3D. Other than that I think 3D is used for animations and in movies too maybe for some effects. Since things get updated every alternate day I'm not sure whether it has been introduced in web designing or not.