How to send emails to multiple recipients

How can I send an email to multiple recipients without having all recipients get to see the entire list of email addresses of all the other recipients?

A bad idea is to use the field "TO" and to write all of the e-mail addresses in this field like that:

TO: recipient1@example.com; recipient2@example.com

This rather leads to the fact, that all recipients are able to see the addresses of all other recipients. Especially if we want to send a newsletter, we should avoid this. First, every spammer would be happy about such a newsletter, because he gets a potentially significant number of e-mail addresses all at once and second, we run the risk to get our email itself in the spam folder of the addressee, because the email program can think, that this is a mass mail with this huge list of recipients.

The solution

The solution is called BCC (blind carbon copy). In the normal field for the receiver, we write our own address (in the example me@example.com) and in the BCC field, there is our list of all recipients:

TO: me@example.com
CC:
BCC: recipient1@example.com; recipient2@example.com

All recipients in the BCC field remain invisible to all other recipients. Thus, each recipient only sees the address of the sender in the TO-field and all other addresses remain unknown and we protect the data.

Why should my address in the recipient?

Now you may wonder why you should write your own e-mail address in the recipient field. You may think that this makes no sense, because you will get the mail with this yourself and you do not need to receive it after you have written it.

The problem is that, unfortunately, we have to specify at least one recipient. Otherwise our mail program complains. Of course, we can just add one of the addresses from the recipient list to the "TO"-field, but with this, at least one recipient would be no longer invisible to the others. Another solution would be to write just any address to the field, but that is no solution either, because the content of the mail should no be sent indiscriminately to someone.

Therefore, we take our own address. Because the recipients know this address anyway and we already know the contents of the mail.

The correct delimiter

Outlook uses the semicolon as a separator between the email addresses. Other programs may use the comma. In general, both delimiters can be taken. If you don't know, you can just test it, which separator is working in your mail application.