Your post title is emblematic for the times we're living in, but nevertheless makes me shiver.
Glass-fiber christmas trees anyone ?
You could run it on the server nightly, or have someone kick it off.
Either way, you may want to compare the birthday to a "last card sent" date, so that if the user (or even the server) doesn't run it for a day, you don't skip sending. Just a thought.
siplus Kind of with you, but then, I always thought most birthday cards (and xmas trees, for that matter) were pretty impersonal anyway. I past the shivering stage long ago, when holidays got cold and impersonal, which may have been before they went digital. Makes me look for, and try to provide, sincere good wishes wherever I can, and pretty much ignore the trappings from Hallmark and Wal-Mart and the like. Just sayin'.