How do I send an email to more than one person? (9/24/08)

The basics
If you want to send the same email message to more than one person, most email programs let you put each person's email address in the "To:" field of your message, usually separated by commas or semicolons. When you've finished writing it, you just hit Send as usual. While this is the simplest approach, it may not be your best choice. And, in certain instances it may actually get you into trouble.

"To" vs. "CC" vs. "BCC"
With most email programs, when you compose an email message to more than one person you can choose to put any email recipient's address into any of 3 fields. Each field has a different meaning and function. No matter which field you use, every recipient will get your message.

To: The people to whom you're "directly speaking." For example, if you're asking a question, you should reasonably expect these "primary" recipients to reply.
CC (carbon copy): Additional people to whom you want the message visibly delivered, but you probably don't expect anything back from these "secondary" recipients.
BCC (blind carbon copy): Additional people to whom you want the message invisibly delivered. Their addresses are hidden from the other recipients. (If you don't see a BCC field when you're composing an email, there is probably an option to reveal it somewhere in your email program, enabling you to use it.)

Every recipient will receive the same message. Only the recipients in the To and CC fields will be listed in the email when it arrives. In other words, everyone you put in the BCC field will also receive the message but they won't be listed, so only they (and you) will know they received it.

Example 1: A small-scale message
Here's a small example of an email you might send to 4 people in a company that you're working with:

  To: JoeEmployee@TheCompany.com, FrankEmployee@TheCompany.com
  CC: MaryManager@TheCompany.com
  BCC: TomVicePresident@TheCompany.com
  Subject: Thanks for your help creating the new ice cream flavor!

This message will be sent to all 4 people. Everyone will see that it's directed at Joe and Frank, with a copy to Mary. However, when your message arrives, neither Joe nor Frank nor Mary will know that you've also included Tom.

Example 2: Small-scale announcement using "To"
Here's an example of an email you might send to announce something to a handful of people:

To: (list of a few email addresses)
  CC: (empty)
  BCC: (empty)
  Subject: Ice cream testers needed in our Boston lab!

This approach, while simple, does reveal everyone's email address to every other recipient on the "To" list, so you should only use it as appropriate.

Example 3: Large-scale announcement using "BCC"
Here's an example of an announcement (or notification) email you might send to many people:

To: (your own email address, see below for explanation)
  CC: (empty)
  BCC: (list of many email addresses)
  Subject: New ice cream flavor now available in all our shops nationwide!

This is the best way to send out an announcement to a larger group. Using BCC in this way has a number of advantages:

You won't reveal anyone's address to anyone else. All of your recipient's email addresses (whether they're customers, colleagues, vendors, etc.) will be hidden, except for yours.
It makes the delivered message shorter, since it won't list all the recipients.
It eliminates the risk of "accidental Reply All," i.e., that some of your recipients may accidentally reply to "the sender and all other recipients," instead of replying to "the sender only." Your use of BCC prevents their "Thanks" or follow-up message from going to everyone else, which can be confusing or inappropriate.
Since it won't reveal all those other addresses, any viruses or spyware that might have infected an unprotected recipient's machine won't be able to "harvest" those addresses and then send viruses, spyware, or spam to them.
Similarly, if one of your recipients forwards your message to anyone else, they won't in turn be able to harvest any of those other addresses, either.

In this example I also suggest that you put your own email address in the To field. Technically you could leave the To field blank, but:

A message from you that arrives addressed to no one might look a bit odd, and
You'll also receive the same message that everyone else gets, so you can see it for yourself.

When you're done, you'll have two versions of this message:

Your copy of the message you sent (with every recipient listed, including the BCCs) in your Sent email folder, assuming your email program keeps copies of messages you send.
Your copy of the announcement you received (showing one recipient: you) in your Inbox.

Getting yourself in trouble: Too many recipients
However, before you create an announcement email, put 500 people in the BCC field, and then click Send, you should be aware that your ISP (e.g., Comcast, Verizon, RCN, etc.) might not permit you to send such a message:

Your ISP may refuse to send the message because it exceeds their "email send" limit (a.k.a. "SMTP Rate Limit"), which may only let you send email to no more than, say, 100 people per message, or 500 people per hour, or 1,000 people per day, or some combination of limits like these.
Your ISP may also tag you as a spammer and completely shut off your ability to send any email with no notice. After that, every email you try to send will fail with an error message. You can usually clear this up by calling their customer service department, but it's better to avoid it entirely.

Note that when either of these problems occurs, the error messages you get probably won't explain what's going in plain English.

Here are two ways to avoid these problems:

Break your recipient list up into "chunks" of people, below your ISP's limit(s). Under the example limits above, to notify those 500 people you could send 5 messages with the same Subject and Body to 100 people each, all within one hour. But then you couldn't send even one more message until the hour was over, so to be safe you should actually send them over two hours, or to even fewer people per message over three hours, etc. This time-consuming and labor-intensive approach is only practical if you don't do this very often.
Look into services that can do this for you. For example, I don't actually send this newsletter to you directly. I use a service called Constant Contact, which handles all the email delivery work for me. Most of the better services have a monthly fee, but if you send such emails often enough it's probably worth the money.

Where to go from here

Before you send an email to multiple people, think about whether you want to reveal everyone's address to all of your recipients.
Use BCC to enhance privacy and reduce message size, inappropriate email chatter, and the spread of viruses, spyware, and spam.
Ask your ISP what your "email send" limits are, i.e., to how many people can you send email each message, hour, or day and not get into trouble.

If you know someone who might find this helpful, please feel free to forward it.
If you have any comments about this article, send me a reply!
If you have a topic that you'd like me to write about, I'd love to hear about it!