[pyre]

That was my thought as well, but then I thought that the requirements might be different here. git-subtree would allow you to create a git repository (with history) from a directory in a pre-existing repository. You could them just 'git rm -r' the directory from the original repository, but I'm not sure if the requirements here are to completely remove the history of that directory from the original repository too (because git-subtree doesn't do that, to my knowledge).

[timtadh]

I agree, git-subtree doesn't quite do what they do in this blog post, but it covers similar ground and is really easy to use in comparison.