Office 2007 and the law of unintended consequences

The Office 2007 zipped XML file formats are undoubtedly a good thing, but they can cause problems when clever software "understands" that you're using ZIP as a compression format. A couple of issues I've run into so far...

MailMarshal recognises Office 2007 files as zip files and checks inside them. Now some of the XML streams inside an Office 2007 file have filenames like presentation.xml.rels. When MailMarshal sees this, it goes "Oh no! Double file extension! Must be evil scripting virus!" I'm sure other mail cleansers have similar rules. So emailing Office 2007 files around is a bit of a lottery at the moment. (Mind you, this rule also bites people who version their files, e.g. "Design Document v0.8.doc." But you can change filenames, whereas you can't change the Office 2007 file format.)

Typepad recognises Office 2007 files as zip files containing XML. Fortunately, it doesn't unpack them, which is something it does under other circumstances, but it does seem to look inside them to figure out what how to serve them up as, and unfortunately ends up messing up either the content type, content disposition or both (I can't be bothered to do a proper diagnosis). So if I post an Office 2007 file here, and you click on the link, your browser may think it's plain text intended for display, and show you all sorts of garbage. In fact the file is perfectly intact and can be downloaded just fine.

I'm sure that as the Office 2007 formats become more widespread, zip-aware products will become equally Office-aware and these problems will go away. In the meantime, the effect of using a so-standard-it's-transparent packaging format is an interesting example of the law of unintended consequences.