The formal announcement would have been made by the parents. This is done intimately by note, word of mouth and in the local newspaper or social register. Telephoning the Society Editor was a given. If you were a prominent citizen, then they would post your photographs. Engraved announcements were not correct and never done. If permitted, this would be our modern Save the Date as we know it today.
Save the Date Etiquette
Whilst reading my Emily Post etiquette books, I routinely like to ponder why some traditions are not around anymore. Announcing that somebody just got engaged used to be a very formal affair. Days before the formal "announcement" the Bride and Groom wrote to their intimate friends and relatives telling them of said engagement and to not tell anyone else until a specified date. Upon completing that task, these intimate friends and relative entertained the Bride and Groom privately.
Today, with our bustling society and full work schedules, a Save the Date is a must. Guests need to know if they should take off work, and if so, for how long. Travel arrangements must be made if you are having any out of town guests. Send out Save the Dates 8 - 12 months in advance of your wedding day. Earlier is better if it is a destination wedding. All you need are your names, date, city and state and a "formal invitation to follow". You may put your wedding website on your Save the Date. It does not, however, go on your formal invitation.
Although it may not be the 1880's or even the 1920s', our parents do not routinely call the Society Editors at our local papers to inform the world of your engagement. But you can still relax knowing you are not breaking any tradition by sending out a Save the Date. It's just a "must" for today's Bride and Groom. So have fun, get colorful and let your friends know to SAVE YOUR DATE!