Additional Information:

Mailboxes can be found near Inns. Mailboxes have different appearances based upon race and location.

It costs 30 copper to send mail. If you don't wish to pay the postage you can set the mail as C.O.D. for 30 copper. The person receiving the mail must then pay the required fee to receive the mail. This might be useful if you're mailing an item to another person that you're giving away for free. However, some people might be offended if you send them a mail but require them to pay the postage. It can be seen as being cheap. As you become higher level, the postage fee becomes very cheap compared to the amount of money you have.

You cannot send mail to yourself. This would be considered an exploit, since it would allow players to unfairly have additional storage space.

You can send mail to your other characters, which can then be used to exchange items or money.

You cannot mail players of the opposing faction such as Horde mailing Alliance players.

Mail that has been read is now greyed-out.

When all attachments from a mail have been removed (including text), the mail is automatically deleted.

There is a confirmation box for accepting C.O.D mail.

There is a confirmation box for deleting mail that has an item or money attached, when the delete option is available.

If the subject line is not filled in when you put an item in a piece of mail, it will automatically be filled in with the item being sent.
 
Mailing Tips

Check your mailbox when you come back to town. You never know what might be in there!

Make sure you send your mail to the correct person. Their name must be spelled correctly or the mail may go to the wrong person, just like real email!