This is a 3D drawing program I made:
You can make a user account and save your drawings to the server. I really need to write better documentation / make a better user interface; but much of the core functionality is up and running.
Not sure that I'll put much more work into it, just life and all that, but it was a fun little project. (Although I suppose there are a few more loose ends I ought to tie up in it.)
Cheers,
Jonny