This format isn't really that relevant to Unity or WebGL (as othrs have also pointed out).

But you might want to keep an eye out for (Open Game Engine Exchange format) (http://www.opengex.org) which is supposed to be the result of this IndieGoGo campaign: http://www.indiegogo.com/projects/open-3d-model-exchange-for...

It remains to be seen OpenDDL or OpenGEX will ever become more than a single vendor format.