Small, but special
On Ask the Readers on Lifehacker, there's a proud tradition of someone asking, "How do I do X?" and people responding with, "Don't do X! It's bad/offensive/stupid/MAKES YOU A HORRIBLE HUMAN BEING."
Today(...er, yesterday), someone writes in:

This holiday season lots of people I work with or who I'm only loosely acquainted with have asked me for my mailing address so they could send me a holiday card. While I appreciate the nice thought, I don't really celebrate a traditional holiday like Christmas and I don't like giving out my address or getting more snail mail than I need. Call me a big Scrooge, but I'd rather these folks save a tree and their stamp instead of wasting it on a card to me. What's the best way to say "thanks but no thanks" to holiday cards?

A reasonable concern? Not everyone thinks so. (Second and fourth links are different comments by the same guy, but that's because his comments are Very Special.)