Unmined treasures in search meta-data?

It occurred to me the other day that Google (as well as Overture and anybody else with a search engine) is probably sitting on an Olympus Mons-sized pile of search metadata. Google’s zeitgeist exposes some choice pop-culture tidbits, but there’s much more to be had. Imagine if you could track the popularity of an arbitrary keyword or show the top n phrases containing a given keyword. I’m sure there are marketeers who would pay to know such things, and perhaps Google offers that service without promoting it. If they are, I’m surprised I haven’t heard about it from somebody.