check your emails
I received a confidential internal document today via email... sent to the wrong recipient. It seems like today's email programs should be smart enough to question this. Imagine a new feature: when I mail a document with "confidential" in the text or attachment, check that all recipients are in the same domain as the sender. If not, warn the user and also send a log record to the IT staff.
The feature would catch mistakes but also rat out people (I'm thinking "Kevin") who send confidential documents to customers.