Start a conversation with a computer person about privacy and, within perhaps 30 seconds, you will discover that the subject has been subtly, but permanently, changed into a discussion of security. The problem is that privacy and security are not only quite different, they often appear almost unrelated.
The phone company has excellent security over landlines. Typically, the only effective way to listen in on such conversations is to tap directly into the line either at the subscriber's house or the central office switching equipment. Few Americans, as a result, have their phones tapped, and those that do invariably have someone really interested in what they are up to. Radio Shack scanners will not reveal landline phone calls.
Traditional phone service, therefore, is (relatively) secure, but is it private? A judge in the USA has recently ruled that phone companies have a First Amendment right to sell information about your private calls to whomever they wish.
This reveals the true benefit of security: With a secure system, you may rest assured that someone other than you, probably a well-established corporation, will be making a whole bunch of money off of your private information. No amateurs will be destroying your privacy for free.
Even though privacy may be the goal-a potentially elusive one at that-security is, nonetheless, an important prerequisite. Achieving security over a personal network that you may tap into anywhere in the world will require significant barriers.