Here’s evidence that online publications should try to re-use—and make accessible—old content. The most emailed story on the BBC website at the moment—Aug 5 2008—is actually a story from January 2004:
which is this one:
I have no idea why it is—although the subject matter is pretty compelling, I must admit. (The gadget, it turns out, is not half the price it was back then. You can find it here; the BBC link no longer works.)
Bottom line: Some stories are just too good to allow to grow old.
Update, Aug 23: Further to comments, I don’t think this is deliberate self-promotion. I noticed another story near the top of the most emailed list again today, which didn’t offer anyone any obvious commercial benefit. It was on raining fish, a story from 2004: