Nature 412 had an amazing article on very novel development, "Parasitic Computing". Simply put, some guys at Noterdame found a way to utilize/exploit the TCP error-checking algorithm to make users that you are communication with do useful computaitonal work for you. This is technique can be done effectively, we're talking about some very impressive computational resources at one's disposal.

Also of note.. Albert-László Barabási and Hawoong Jeong, two of the people behind this parasitic computing project, are also two of the leading authorities on self forming networks. Barabási authored a book called Linked: The New Science of Networks which is considered one of the "must reads" on the subject. Infact, its the book I was reading when I started work on the mapping the social network on MemeStreams..

New Technique: Parasitic Computing