A9, despite being an Amazon company, is still a bit under the radar. That'll change a bit after some recent pr blitzing. John Battelle was in the pack covering the new face of A9. He's got a little history with Udi Manber though so there's some added value above reports from the other usual suspects.
A commenter on John's blog, counterbalancing the enthusiasm in the piece, pointed out that a lot of the search UI knowledge has been around for a while. (Aside: for any tech article, story, report, paper it's a truism that "Foo did that 20 years ago!"). I think John's piece missed one key element in focusing on searchstream capture. A9 is trying to be of the Web. No highly interactive features. No fancy Flash or Java. Just text, links, styling, and some Javascript.
Another submerged aspect. Searches becoming first class objects and interfaces appropriate for managing them.
And a toolbar! More chrome to kit your browser with, at least on Windows.
Media companies should take very serious note of what A9 is doing. I would think advances in how people search for product might be of interest to them and their advertisers.