Sending email to a group of people is a common occurance.  We often get emails that we have to forward to others, and there's a right and a wrong way to email a list or group of recipients.

The wrong way is to put all the email addresses in the TO: field.  It's also not a good idea, to put one recipient in the TO: field and the rest in the CC: field.  The reason is that you have no control over what happens to that email after you send it. All the recipients of an email are displayed when you forward or reply, if you put the addresses in the TO: and CC: fielsd.

You use BCC (Blind Carbon Copy) to hide any recipients in an email. So when you send your email, it arrives as if it was personally sent to them with their email address only.

All email applications and webmail services offer BCC addressing.  If it not displayed, such as in Microsoft Outlook window to the right, you can Show it permanently by selecting the Options tab in a message window, and clicking the Show BCC button.

This type of addressing should be used for all personal email, unless it's emails that need to be documented or for legal reasons.