When you're creating a Word document from a script you may want to activate something like revision tracking by default. Like the previous Open XML tips this one is surprisingly simple thanks to the power of the new underlying format (and Doug for pointing me in the right direction).
To see it in action, fire up Word and create some content. For example, type =rand(P,L) and press ENTER (where P=#paragraphs, L=lines per paragraph), or type =lorem(P) and press ENTER (where P=#paragraphs).
Following the instructions here edit the word\settings.xml part and add a <w:trackRevisions/> element as the first child of the <w:settings> element. Now when you open the document, revision tracking is on. For more information about revision tracking and what it can tell you when you subsequently open the document via code have a look at this article at OpenXML Developer.