You use Google Trends: http://www.google.com/trends/ http://www.google.com/trends/ What's interesting is that I had this exact idea with precious metals. The

You use Google Trends: http://www.google.com/trends/ http://www.google.com/trends/ What's interesting is that I had this exact idea with precious metals. The frequency of the terms searched (like gold or buy gold) matches the gold spot market index impressively closely.