Most email not only passes through, but actually resides on at least two servers once it is sent by the originator; in many cases the number is greater. When you hit the ‘send’ button, you are not sending your message directly to the intended recipient. In a corporate environment the first stop for your mail is probably your internal mail server (the one where your inbox lives). Email can be intercepted at any point along this delivery chain by anyone with access to those servers, whether that be server administrators at the sender, ISP or recipient. In most cases the reason for failure to adopt encryption lies in the management and administrative overhead associated with creating and maintaining a public key server at the corporate level. At the end user level, the fact that the recipient of the as yet unwritten email has to pre-register somewhere and hand over a copy of their public key to sender before the conversation can even begin, has been enough to make most users rapidly revaluate their need for privacy and just hit the Send button.