Black Square is to specs what Malevich is to code. This release is 0.1 - treat it as a preview, it has not been field-tested at all. There are known important bugs. But if you do feel adventurous, give it a whirl!
Big thanks to Eric White (http://blogs.msdn.com/ericwhite/) who coded the most important part of the system - the document merger.
For more background on Black Square, see the blog post where it was originally introduced: http://1-800-magic.blogspot.com/2009/07/lockingunlocking-word-doc-files.html