There are several possible explanations for the sharp drop in paper Christmas cards that my coworkers and I received this year, says Kate Julian in Slate. The bad economy, for instance, may have contributed to "the year's record low haul." How about the fact that people no longer keep track of mailing addresses, or the unlikely, long-rumored "triumph of the e-card"? Perhaps, perhaps. But one theory gripped us more firmly than the rest: It's Facebook's fault. Here's an excerpt:

Once, not so long ago, people picked out a card they liked, wrote something inside, sent it off, and that was that. Then came the photo card. Even though some people initially found adding personal photos to cards a self-involved move, it soon became the default for people with kids. Meanwhile, the home computer was enabling another innovation: The holiday form letter, an immodest chronicle of a family's Very Busy, Very Exciting year. Somewhere along the way, between the photos and the form letters, the holiday card stopped being a note from one person to another and started being a mass broadcast.

But now, with Facebook so thoroughly insinuated into our lives, we already know where our friends (and our "friends") went on vacation, what they look like right now, and whether they've recently switched jobs.... In 2010, people don't need to wait for December to brag. They've been doing it all year.

Read the entire article in Slate.