In Who Do We Trust?

What is the value of trust? How valuable is trust? How do you know who you can trust (if anyone)? We all recall the Linda Tripp/Monica Lewinsky debacle, right? Shared telephone calls are a breach of trust. It's even illegal to record a conversation without the other person's permission. So, my question is whether sharing someone's e-mail with another person without their permission is a breach of trust?

Recently, I found out a person who I have been corresponding with has been turning around and sharing my e-mails, word for word, with another party. This has apparently been occurring for quite a while. What bothers me is I trusted this person and was writing to them in confidence. Or what I thought was a confidence. I respected the person's opinion and sincerely believed what I wrote to them stayed with them. It's not the content that was shared that bothers me, but the principle of it all. I will now feel uncomfortable when writing this person and will be making an active effort to monitor what I write to them. And, I think this is sad.

Where is the line of betraying the person who is communicating with you? Phones? E-mails? Written letters? Smoke signals?