Appendix D. The PICS Specification

The PICS specification introduced in Chapter 17, consists of two parts:

An excellent article describing PICS is “PICS: Internet Access Controls Without Censorship,” by Paul Resnick and James Miller, Communications of the ACM, October 1996, p. 87. The online version of the article appears at

Rating Services

The PICS rating service specifications are designed to enable many different kinds of ratings services on the World Wide Web. A rating service is any person, organization, or other entity that issues ratings. Ratings can be distributed with the document being rated, by a third-party site, on a CD-ROM, or by any other electronic means.

The PICS standard specifies a syntax for text files that describe the different kinds of ratings that a rating service can issue. This lets computer programs automatically parse the kinds of ratings that a service provides.

In their article describing PICS, Resnick and Miller create a sample PICS rating service based on the MPAA’s movie-rating scheme:

((PICS-version 1.0) (rating-system "") (rating-service "") (icon "icons/moviescale.gif") (name "The Movies ...

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