Codeville is a distributed Version Control System. It began with a novel
idea for a merge algorithm, and has grown from there. It is designed to
be easy to use, and scale from small personal projects, to very large
distributed ones. If you'd like to know why there's need for new merge
algorithms, consider what the lead monotone developer had to say:
http://article.gmane.org/gmane.comp.version-control.monotone.devel/3264

Codeville works by creating an identifier for each change that is done,
and remembering the list of all changes which have been applied to each
file, and the last change which modified each line in each file. When
there's a conflict, it checks to see if one of the two sides has already
been applied to the other one, and if so, makes the other side win
automatically. When there's a non automatically mergeable version conflict,
Codeville behaves in almost exactly the same way as CVS.