[puzzle]

On the other hand: 1) this kind of query is not a big driver of Adwords revenue 2) the direct answer is cheaper to compute than a search of the web index 3) this result page is much smaller to generate, serve, load and render

[dfcowell]

4) they are still showing ads on the page.

[puzzle]

I don't see any ads for the query mentioned, but I guess that's a possibility for the future.