"Versioning" is a pretty neat idea. I am not sure of the history of Subversion or Mercurial. But I know that GIT came about because Linus Torvalds..."needed" a version tool. So he wrote one. I find myself doing that all the time.I have a ton of little tools I write for this and that. I don't post even a portion of them. Certainly not the one I use regularly. I enjoy Open Source, but there is something to be said about security.