On Social Bookmarking, Spam - and Steganography

A fine analysis of the threats posed to social bookmarking sites (del.icio.us, digg.com etc) from Alex Bosworth. But for me, the real corker is his idea of steganographic spam.

Steganography involves hiding something in a message so that it is not even apparent there is hidden content - unlike cryptography, where the content is obscured but its presence is obvious. This might be achieved by hiding a message in the pixels of a picture - few enough for their presence not to be obvious to casual observers - that can be extracted using the appropriate software running the right algorithms.

Bosworth would have us imagine steganographic spam - so subtle, we are not even aware that it is there. Fiendish.