Christmas card experiment--for years and years I made about 80-100--I sent them all over the place *usually one style card-mass produced by moi! So, I started to get less and less cards back (I think the internet was the culprit/or just plain NO card senders)...then the following year I was pounded with cards...then not so much. Then, I stopped the massive mailing and just made a 25ish who sent to me (I thought this was silly-and decided to go back to massive mailings)...
I don't really know if it is a "theory" or if some people skip a year/2 years and then pound everyone with cards? Maybe it's all about the postage? I do love receiving Christmas cards so I will keep our PO in business for years to come!