Do you qualify for a printed card?
So, left to my own devices (always a dangerous thing), I am left with sharing my opinion. Perhaps it will help start the discussion that leads to the formalization of the etiquette.
I believe a printed card with a handwritten signature is by far the best card to receive. There is nothing more personal and real than a card delivered in this manner. I would consider it mandatory for your family members on important holidays, but also for your key clients. I would even be happy with printed cards with signatures handwritten, yet either imprinted or part of the printing of the card.
In regards to electronic cards...These are best used for distant relatives, FaceBook and social media connections, and impersonal email marketing. I've tried sending them out a few times during the holidays or on birthdays and felt cheap and dirty inside. Imagine sending a holiday card of the kids in an email. The whole purpose is to share in the holiday spirit and give a nice picture of your children to family and friends for them to hang on the wall or fridge.
There are times when timing is an issue and it is more important to have the card be to the recipient on time instead of late. This is a case-by-case situation and the urgency and decision is best left to you and your organization.
If you have links to or information in regards to this subject please share.