Bcc Means Privacy and Efficiency with Group Email
   I'm sure you know these emails that were obviously sent to a group of people: everybody's email address is in the To: (or the Cc:) field, forming a long, long list. This not only looks odd and unprofessional, it also exposes the email addresses of people who may have wanted to keep them private.
     1. Create a new message in your email client.
     2. Insert "Undisclosed Recipients" in the To: field, followed by your email address in "<,>" braces.
     3. The To: field should look like: "Undisclosed Recipients <me@example.com>".
If you send emails to undisclosed recipients frequently, you can add your own email address to your address book with "Undisclosed" as the first and "recipients" as the last name. Instead of filling in the To: field manually, you can then use the address book entry. Put all the recipients' email addresses in the Bcc: field, separated by commas. The Bcc: field could look something like: "my.first.friend@example.net, my_second_friend@example.net, stillanotherfriend@example.com". Compose your message. Send it.