"If you search for hidden messages on the Web and find nothing, what should you conclude -- that there are no messages, or that the terrorists are too sophisticated, and your tools don't work?
The answer to this question turns out to be a highly personal one, a matter of individual psychology and interest rather than a reasoned decision based on collective safety and the immutable laws of math. Ask security types, or people who make software to aid security types, and they say that steganography is a grave threat to our safety. Defenders of steganography, and its cousin cryptography, take the opposite view." More at Salon.com.