http://vww6ybal4bd7szmgncyruucpgfkqahzddi37ktceo3ah7ngmcopnpyyd.onion/it/security/human-security/message-hygiene
For example, if you filled out an order form using your organizational credit card, and emailed it to a vendor as a PDF, someone who breached their email account would have access to a document containing your credit card information for as long as it was not deleted from the server.