The Army has an exemption for its Force9 online game site, as it is aimed at a "specialist audience", potential Army recruits.

An "umbrella" exemption has also been granted for sites which use PDF documents which will be difficult to convert to HTML. Agencies operating such sites will have to provide an HTML paragraph describing "the key messages" of the PDF document.

Usability expert Jakob Nielsen has called PDFs "The Creature from the Black Lagoon" and pronounced them "unfit for human consumption".

Although accessibility is often thought of as a problem for disabled people, Bruce points out that over-elaborate websites and those demanding nonstandard plug-ins can "disable" mainstream users with basic browsers or a low-speed connection to the internet. Most people, more-over, develop some kind of disability affecting web use with age, he says. Disability activists are also strong on this point, often referring to the general population as "the temporarily able-bodied".