[falien]

I wonder if anyone has actually attempted this and seen how dense you can pack it and reliably recover. I imagine you would need measures to counter small misalignments when rescanning and imperfections in the physical media.

[blasdel]

200kb per A4 page using a 600dpi b/w laser printer: http://ronja.twibright.com/optar/

[seancron]

Take a look at http://www.ollydbg.de/Paperbak/index.html It encodes the binary onto paper and uses Reed-Solomon ECC to restore unreadable data.

I've tested it out myself, and it's only after you start to crumple it together that it stops working. I tested it with an inkjet printer though. A laser printer may stand up better.