From http://lists.w3.org/Archives/Public/public-comments-wcag20/2006May/0119.html
Some parts of Web accessibility are not under the control of the author. The user agent, like a browser or screen reader (the latter of which is definitely included in WCAG 2's definition of ""user agent""), has a significant role to play. Nonetheless, WCAG lists these requirements:
More than one way is available to locate content within a set of Web units where content is not the result of, or a step in, a process or task.
Why can't people be expected to simpy use the Find command in their browsers, or the back button?
The same issue reappears in that classic bugbear of Web-accessibility pedants, hyperlinks:
Each link is programmatically associated with text from which its purpose can be determined. [...] The purpose of each link can be programmatically determined from the link.
""Purpose""? Doesn't Slashdot have an enormous mass of code in its system to prevent people from linking to notorious vulgar images in the guise of a real hyperlink? (There the ""purpose"" is to deceive.) The ""purpose"" of a link is to provide a link, obviously.
Did they not mean the ""destination"" of a link? If so, how is it not obvious from the semantics of the link? Isn't it embedded right in the a href=""""? How is it impossible to ""determine"" the destination of a link? That's the user agent's job, is it not?
Incidentally, there have been a few experimental all-sign-language sites in which many links and their targets are given completely in sign language. There is no link text per se. What's between <a> and </a> is a video file or image of a person using sign language, and where you end up is another such video file or image (or a page full of those). Given the semantics of all markup systems in use on today's Web, the hyperlink has to contain text characters in order to function. A still image has to contain an alt text (though alt="""" is plausible in some cases).
Nonetheless, there are a few scenarios in which a page intended to be accessible to sign-language speakers uses no text at all. How is such usage accommodated in WCAG 2? (And must authors, by implication, use an interpreter to voice the sign language for blind visitors, which must then of course be captioned or transcribed? Where does it end?)