BCC, blind carbon copy, is a tool to send an email to someone and share it with a third person without the primary contact knowing it.
Have you ever been copied on an email, the contents of which were sent to you just as an FYI? Then before you know it, you’ve received 5 or 10 more emails that are follow up questions or debates that don’t affect you? With BCC, when the recipient hits reply, it only goes back to the original sender saving everyone time.
If you send an email to a list, just address the email to yourself and put the recipient’s email in the BCC field. This prevents the swarm of emails that may arise if the recipient clicks “reply all”.
This practice also protects the recipient’s email addresses in case one of them forwards the email beyond.