Inspired by EtherPEG, Driftnet is a program which listens to network
 traffic and picks out images from TCP streams it observes. It is
 interesting to run it on a host which sees a lot of web traffic.
 .
 (Obviously, this is an invasion of privacy of a fairly blatant sort.
 Also, if you are possessed of Victorian sensibilities, and share an
 unswitched network with others who are not, you should probably not
 use it.)