Yahoo! Clues is a new beta service that gives you a unique "behind the scenes" look into popular trends across the millions of people who use Yahoo! to search each day. With Yahoo! Clues, you can discover and compare trending information for search terms of interest to you, or explore popular trending search terms on Yahoo!
You can see search volume charts, demographic graphs, maps, or even related searches specific to a demographic group. Yaoo's also experimenting with a feature called "Search Flow," which offers a unique look at people's search patterns and the next most probable search term people try after searching for a query.
Watch this short video of a tour of the product with examples that highlight some interesting uses for Yahoo! Clues:
More Info: Yahoo! Clues