Cards come under the general overall category of “social correspondance”: they’re an informal (and commercialized) version of the “personal note”. I don’t send cards for formal events like weddings unless I’m having an uncharacteristally modernistic mood swing, but I do send notes. Times when etiquette requires you to send notes are:
– when you hear that a friend has become married, had a baby, gotten married, graduated, published a book, been promoted, or returned from a journey — you send a note of congratulations.
– when you hear that a friend is sick; has suffered the loss of a relative, a friend, a pet, a job, a marriage — you send a note of sympathy.
– when you hear that a friend is engaged, setting out on a journey, starting a new business, standing for examinations — you send a note of good wishes.
– when you have eaten out as someone’s guest or stayed in their home or received a favour, you send a note of thanks, and when you receive an invitation you send a note accepting or declining the invitation, and when you realize you are out of touch with someone you send them a note of greeting or better still a note of invitation to tea or lunch or dinner or the theatre.
It probably shouldn’t come as a surprise to anyone that social correspondence is being neglected nowadays. When was the last time you received (or sent?) *any* of the above notes? We just had a poll where the majority agreed it’s better to have folk check a box on a reply card than rely on notes of reply. I’ve noticed that people under forty or so if they do choose to send any of the above notes, send them by email or facebook. Weddings don’t make anyone more entitled to social graces than do any of these other situations, so it isn’t reasonable to expect people who spend more time with a keyboard under their fingers than a pen in their hand to change their communication media for that one purpose.
Blossom bee has a good point: etiquette should make you examine your own behaviour, not pass judgement on others. If you find yourself wishing wistfully for a note, why not examine whether someone else might not be owed one from you and send one off.