If all the headers are invalid or expired, you will see a warning message. As a rating method, it is sufficiently flexible to be extended to other electronic media such as CD-ROMs, and conceivably audio CDs, television programs and the like. For a content developer, installing PICS usually means running a PICS generator such as this one , and including the resulting META data in the document header. PICS allows for generic and specific labels. Generic labels apply to any document whose URL begins with a specific string of characters.
Specific labels apply only to a given file.
In version 3.0 of Internet Explorer, the browser first checks the document itself for PICS data as Metadata in the document head, and also as an HTTP header. It does not check for an index page in the current directory. Thus in Internet Explorer, specific labels override generic labels. The only generic label is that of the homepage. Note that where a for option is used, in declaring a generic label, that the specified URL must match the one that the user sees.