The greeting card industry show little signs of slowing down.
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As far as the postal service? I’m not sure, I didn’t continue digging; however, sales were strong in our area.
Holiday cards are sent out by many, including businesses. There are people that just truly enjoy the sincerity of a card that someone took the time to send to them. A printed email and hanging it up, just isn’t quite the same for a lot of people.
I’m sure that yes, eventually there will be a difference, but letter writing still happens and the USPS is still functioning. I don’t see either going away, anytime soon. IMO.