Googles’ insights for search - the recently added tool to discover what users are searching for has even more new features added:
Data sources now handles all the data from Googles news (to find out what rapidly updated content users read), images and even products searches (ideal if you’re looking to find trends in what people are buying).
Metro sources (US only - at the moment) can determine the trends down to geographic area - perfect for targeting Adwords campaigns to certain areas.