Why did calling cards ever go out of fashion? Sure, we have hundreds of ways to bombard each other with introductions online (or in person…do people still meet that way?), but calling cards had style.

From The Art of Manliness (wow, what a great blog name!):
In the 19th century, gentlemen used calling cards to formally introduce themselves to new acquaintances and to call upon friends and relatives in a dignified way. But there was another type of card used when a gentleman wanted to get the ball rolling with a lovely lady in a more casual way: the acquaintance card.

The cards were designed as a comical way for a gentleman to break the ice, start a conversation, and flirt with the opposite sex. Sometimes the humor was overt, and sometimes it derived from the way the messages parodied the formal rules of etiquette — it wasn’t actually considered appropriate to ask for your calling card back or volunteer your escorting services so directly, as some of these cards do.

Now THIS man is willing to risk his gun, his dog and his shoes to be acquainted with a lady.

Source
Also, check out this Acquaintance Card Flikr Set!