How to Send Email to Undisclosed Gmail Recipients
To send a message in Gmail with all email addresses hidden:
How to Make an Email Group in Gmail
If you frequently send messages to the same group of recipients, consider creating an email group in Gmail: Undisclosed recipients When composing an email, type the name of the new group in the Bcc field. Gmail will populate the field with the complete name, and no one in the group will be able to see the addresses of any other recipients.
No Mass Mailings
You can’t use these methods for large mailings. According to Google, free Gmail is meant for personal use, not for bulk mailing. If you attempt to add a large group of recipients in the Bcc field, the entire mailing may fail.
What About Reply All?
Email addresses in the Bcc field are copies of the email only. If a recipient chooses to reply, they can reply only to addresses listed in the To and Cc fields. For this reason, Bcc is a great way to stop a reply-all chain before it starts.
