Google Trends is the application by the Google which gives a list of the hottest search trends which are currently in vogue.
It is very useful expecially for the seaon based services and products. We can actually check which is the best time to promote the products with the help of Google Trendz.
Google Trends is a public web facility of Google Inc., about Google Search, that shows how often a particular search-term is entered relative to the total search-volume across various regions of the world, and in various languages.
google trends is very good tool for mining "current trends" - but not enough to go on by itself -- use with other keyword sourcing tools for best results.
http://www.google.com/trends Wikipedia: "Google Trends is a public web facility of Google Inc., about Google Search, that shows how often a particular search-term is entered relative to the total search-volume across various regions of the world, and in various languages. The horizontal axis of the main graph represents time (starting from some time in 2004), and the vertical is how often a term is searched for relative to the total number of searches, globally.[1] Below the main graph, popularity is broken down by region, city and language. It is possible to refine the main graph by region and time period. On August 5, 2008, Google launched Google Insights for Search, a more sophisticated and advanced service displaying search trends data."
Now you know trends, you can also use Google insights, which is my preference www.google.com/insights/search/
google trends is another useful features by google, you'll see what keywords and key phrase are being use in different places. You'll see whether the keyword you want to target is being use in the place you to market.
Yeah, trends is good but you want to use it along with other tools - not something to rely on all by itself.