Nice article. Have you considered any pro-active methods at all? For example - DocTracking.com lets you "tag" your Word/Excel/Powerpoint/PDF/etc files with invisible tracking, and it reports back to you the location and identity of anyone using your documents.

If you're sending confidential info to anyone, it's always nice to be able to keep track of where that info ends up, or even just planting tracked documents in your own PC is a really good way to get an instant alert if someone somehow plunders your files one day in future :-)

Wow... I started reading articles and following links to your other articles, and you are seriously impressive. This is great information, and it's a shame more folks don't know about it. I'm definitely going to be doing some researching tonight. Thanks so much for sharing what you know with the rest of us!