Eh?
• This is a good thing. Why?
•
•Easier navigation through document, i.e. one ‘tab stop’ per UI control.
•Gives keyboard access to widgets.
•Manages keyboard control within widgets.
•Establishes relationships between elements within widgets (e.g. parent/child/sibling in tree-view navigation).
•
(This is quite technical.) Why is this “a good thing”?

Allows easier navigation through document, i.e. one ‘tab stop’ per UI control (e.g. “I don’t want to have to tab through this long list of links”)
Gives keyboard access to widgets.

Manages keyboard control within widgets.

Establishes relationships between elements within widgets (e.g. parent/child/sibling in tree-view navigation).

Example:  Google Reader using Google’s AsxJAX framework (http://code.google.com/p/google-axsjax/) Greasemonkey script.