Still and moving images, usually of women, in varying states of nudity, posing or performing erotic acts with men, women, animals, machines, or other props. Some say it degrades women, some say it corrupts young boys (who down-load it from the web or exchange it on floppy disks). Most of it is in the form of JPEG images. Many websites offer porn of all sorts, almost always for a subscription. It is said that these are a driving force in the evolution of new technology and techniques for the web. Advertisments for them certainly constitute a significant proportion of all spam. There are even pornographic computer games, an early example being Mac Playmate.