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 http://w3.org/PICS/iacwcv2.html.
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 "http://moviescale.org/Ratings/Description/") (rating-service "http://moviescale.org/v1.0") (icon "icons/moviescale.gif") (name "The Movies ...