You use the BCC entry for the addresses instead of TO or CC. This will make your emails easier to read, people don't have to scroll down thru a long list of names, and also protect the email addresses of those you are sending to, spammers will not be able to get the addresses off the email to use for spam. Quite often emails get forwarded and you do not know where the list will end up.
When you put email addresses in the TO and CC lines then everyone that gets the message knows who all it was sent to. BCC is useful not just for sending messages that have lists of names, but also when you do not want everyone to know who were certain recipients. The caveat on BCC is that on some email systems you will not be able to see after send the message who the BCC recipients were. However in Outlook and Yahoo email (where Bellsouth and AT&T email are now) you will see in your sent the BCC list. There is not really any difference in how the addresses in TO and CC are treated in email. Back in the typewriter days the CC did not get an original but a carbon copy (which is where CC comes from). BCC is Blind Carbon Copy.
To use BCC you will look for a line by TO and CC and enter the addresses there like in TO and CC. In many email systems the BCC shows automatically. In others you need to either click a button to reveal BCC or if you go to using your address book the option is there and then you can type in more names one you return to the message.
Using BCC will make your email friends happier, make your messages more professional and help limit accessibility of email lists for spammers. This is good netiquette to use.
Thanks Clay for the suggestion.