What is Machine Learning?

Google Flu Trends estimated how much influenza was circulating in the United States from what people typed into Google, a week or two before the government's own figures arrived. Nobody wrote a rule saying which searches mean flu. The data chose: a team led by Jeremy Ginsberg reported in Nature in February 2009 that, from 50 million candidate search terms, their method kept the 45 whose weekly counts best matched the share of doctor visits for flu-like illness recorded by the US Centers for Disease Control and Prevention (CDC). Flu Trends estimated each week's flu level with a lag of about one day, where the CDC's surveillance took one to two weeks.