A friend and I built http://www.bld3r.com as a vastly more open 3d file sharing platform than thingiverse. We welcome this move, as we prefer files to be hosted on open platforms like github. I thought I'd plug the site for anyone who wants an alternative. We are still in beta, but are finishing that soon.
I mean open in the sense that they have clear terms such that they don't effectively own your content. In building a 3d printing social network, not having to trust us was important to our design.
If github would make import/export a lot easier than it is today it would qualify as an open platform. Right now only the 'git' part of it is open (and git was open all along).
