Comment: the term 'web unit' needs some examples about when the term 'web page' may not apply
Proposed Change:
add some examples to "..may not apply" such as 'webcast' or 'multimedia object'
We have replaced the term "Web unit" with "Web page" and have modified the section on new terms, http://www.w3.org/TR/2007/WD-WCAG20-20070517/#new-terms, to describe our use of the term "Web page" in greater detail. We have also added an example of content that may not immediately be recognized as a "Web page." See http://www.w3.org/TR/2007/WD-WCAG20-20070517/#webpagedef .
Web page
a resource that is referenced by a URI and is not embedded in another resource, plus any other resources that are used in the rendering or intended to be rendered together with it
Note: Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.
Example 1: When you enter http://shopping.example.com/ in your browser you enter a movie-like interactive shopping environment where you visually move about a store dragging products off of the shelves around you into a visual shopping cart in front of you. Clicking on a product causes it to be demonstrated with a specification sheet floating alongside.
Example 2: A Web resource including all embedded images and media.
Example 3: A Web mail program built using Asynchronous JavaScript and XML (AJAX). The program lives entirely at http://mail.example.com, but includes an inbox, a contacts area and a calendar. Links or buttons are provided that cause the the inbox, contacts, or calendar to display, but do not change the URL of the page as a whole.
Example 4: A customizable portal site, where users can choose content to display from a set of different content modules.