I was a bit bullish on the Amazon move to open up their Alexa search API. It appears that people are just starting to use the Amazon Search API to create interesting indexes. I can't imagine any of these examples being greenlighted at the big search companies, because they are such small problems. But, they are certainly small problems that are nice to have solved:

From the Alexa - Web Discovery Machine blog.

* Camera image search - Lets you see what pictures taken by different cameras look like
* Robots.txt Search - Lets you see who's getting blocked by whom
* Zip File Search - Lets you search for files buried in zip files on the Web

It'd be cool to see some social search applications built on top of the platform.