I came across an interesting little program called PaperBack. WTF:

PaperBack is a free application that allows you to back up your precious files on the ordinary paper in the form of the oversized bitmaps. If you have a good laser printer with the 600 dpi resolution, you can save up to 500,000 bytes of uncompressed data on the single A4/Letter sheet. Integrated packer allows for much better data density - up to 3,000,000+ (three megabytes) of C code per page.

Guess it's similar to QR Codes. I'm not sure how useful it would be in the real-world considering you can get a zillion times the storage capacity with a 1.1x1.5cm MicroSD card.

Anyhow since the concept blew my mind I gave it a try on my Canon MX860 inkjet/scanner at 200dpi print and 600dpi gray scan res on some random document, with AES encryption enabled within the program. Worked beautifully! Didn't work when I bumped up the density to 300dpi, but the instructions told me that anyway.

Program link with instructions and optional GPL'd source-code for anyone bored:

http://www.ollydbg.de/Paperbak/index.html

3 sheets of A4 paper = roughly 1 floppy disk

fail

Reminds me of the idea that you can tie a memory stick to a carrier pigeon and use that instead of broadband. The bandwidth is great but your ping times are awful.

That's 400k per image, that's not too bad?