That's kind of cool! I admit that I have received several QSL cards, but have never sent any.
I guess because my interest in amateur radio is centered around emergency communication with whom I want, when I want rather than talking with a random person, I never put much stock in logging contacts or QSL cards.
Getting one in the mail is really neat, though.
Looks like 90% of the cards in that article were from CBers, which tend to be a little more . . . flamboyant . . . than ham operators!