Google Trends
Rated • 122 reviews • cyberculture, search, sociology • google.com
Google Trends plots the rate of searching for terms of your choice over time, and shows the geographical distribution of searches. It also allows you to compare one search term with another.
I learn, for example, that more people in Portland search for 'oolong' than any other five cities put together; similarly an amazingly large proportion of all 'trigonometry' searches are from the Philippines (in the US, which is number nine in the list of top trigonometry searchers, most people just enter 'trig').
A comparison of searches on 'love' and 'sex' is similarly fascinating - far more Filipinos seem to be looking for love than anywhere else; it is about the only country in the world where more people are searching for love than sex. Love makes it into the news a lot more, though...

