I've noticed that many TS/TOS people use "CC" ("carbon copy") to send emails to multiple recipients.  Whenever the mailing is of the nature of a newletter or mass-mailing, this is not generally a good idea, especially in these days of rampant spam.  Today I found a article on about.com that clearly explains why and how to avoid misuse of Cc:

The Shortcomings of Cc:

When you send a message to more than one address using the Cc: field, both the original recipient and all the recipients of the carbon copies see the To: and Cc: fields including all the addresses in them.

This means that every recipient gets to know the email addresses of all the persons that received your message. This is usually not desirable. Nobody likes their email address exposed to the public.

Full Cc: fields also don't look all that good. They can become quite long and grow big on the screen. Lots of email addresses will overshadow little message text.
Bcc: — Blind Carbon Copy

The long version of "Bcc" is "blind carbon copy". If this gives you the image of an empty sheet of paper — a carbon copy without text —, that's not quite what email's Bcc: is up to.

The Bcc: field helps you deal with the problems created by Cc:. As it is the case with Cc:, a copy of the message goes to every single email address appearing in the Bcc: field.

The difference is that neither the Bcc: field itself nor the email addresses in it appear in any of the copies (and not in the message sent to the person in the To: field either).

The only recipient address that will be visible to all recipients is the one in the To: field. So, to keep maximum anonymity you can put your own address in the To: field and use Bcc: exclusively to address your message.

Bcc: lets you send a newsletter, too, or send a message to "undisclosed recipients".

full article:http://email.about.com/od/emailnetiquette/a/cc_and_bcc.htm