In AU they have to figure out what constitutes compliance. Does it just pop up an alert box or does it do some tests. Right. except PNG and CMG or whatever, image formats. How do we deal with formats that are not W3C but that are essential to operation of page. With realaudio, i would imagine that a huge percentage of blind users love it.
Every day there can be a new plug-in on a site.
A tool would have a bunch of recognized mime type. When it sees a new mime type it flashes a manual warning to the user. WC Seems related to 8.1. When new type comes along informs the user of the tool. CR Have map file, can convert.