http://www.fbi.gov/hq/lab/fsc/backissu/july2004/research/2004_03_research01.htm
http://en.wikipedia.org/wiki/Steganography
http://www.jjtc.com/stegoarchive/stego/software.html

"Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message is clear, but the meaning is obscured."

Now, Image Steganography is very much out there. But for instance, out of the gigabytes of images that have seen 4chan.org, iichan/wakachan etc how many, or what extent could you say that there is an image actually hiding some data? What's not to say that the hentai or porn or even a picture of your mate is actually hiding something?

Discuss.