CDs, tapes, external drives, off site back up through Amazon S3; all of these are viable options for backing up precious data.
But what about paper?
Crazy? Well, not really. A programme called PaperBack will take files and render them as code on standard paper. Simply print and file. To recover files, scan the paper. Still, what's the advantage?
Well, one big one is that technology comes and goes. We had ZIP drives, tape drives, and all kinds of stuff before now that aren't used anymore. Meanwhile TWAIN, the standard protocol for scanners, has been around for almost two decades and isn't likely to go anywhere soon.
Sure, you wouldn't want to back up, say, your ILS database like this. But how about important circulation data? Passwords for those days when an act of god wipes your data centre from the face of the earth? You could send updates to rural areas with limited internet access. And in the end, it uses a medium that's been with us for thousands of years.