It was when cabinet ministers began to say that she could not go on that I became confident enough of the trend to predict the end of what had been an exciting period in British politics.
For some things, like retail sales, the categories into which Google classifies its search-trend data correspond closely to what people may want to predict, such as the sales of a particular brand of car (see chart).
Experts say the next big trend in data is going to be geolocation, and the power to predict where you're going to go next and who you spend the most time with.