Google Trends shows how often a topic has been searched for on Google over time. It's the only tool that helps you compare the relative popularity of gadgets (iPod vs Zune), celebrities (Britney Spears vs Paris Hilton), etc in specific countries.
Unfortunately, this hugely popular buzz-tracking service from Google Labs is now lying in a neglected state.
Google's initial plan was to feed new data to Google Trends monthly but we saw the last update on November 21, 2006 - the service has not been updated with the search trends data since the past three months now.
There's a request thread in the Google Trends discussion group to resurrect Google Trends but without any official response. Markus Frind is wondering if Google shut down Google Trends forever.