Google launched Google trends over 3 years ago, and in that time, we have all become addicted to watching trends develop and spread during the year and feasting on the annual zeitgeist.
Now, Google has announced in its blog the launch of a gadget to track trends on your own website. You will need to customise the code as currently Google seem to be having an American Idol moment, which may prove totally irrelevant to your website! Just enter the five search terms you want to track into the code for the gadget and embed it on your site. More info on Google trends is here.