If you've ever sent an email to a group of people you probably wondered how to hide email addresses or lists. Maybe you've been hit by a lot of spam and you may wonder which of your friends or services are distributing your email address. Used correctly, Blind Carbon Copy (BCC) is the field used for email addresses which are hidden from other recipients.
To: This is where to leave the address field blank.
CC: Carbon Copy is where to leave the address field blank. Adding addresses here is the most common way your email gets shared.
BCC: Blind Carbon Copy is where you enter the individual email addresses or the list of your email addresses.
It is email etiquette to hide a friend's or client's email addresses when sending an email. Ignoring common courtesy can lead to devastating consequences for you or your lists. Email addresses can be used for profit and for malice. They can be sold to data lists for direct mail marketing thus increasing spam in your email box and anyone else's email that was listed. Some of your friends or clients may be upset at you (quite rightly they will!). An email address can be used as a disguise for a spammer's redirected email address.
In conclusion, only the BCC hides email addresses so use other address fields appropriately.