Open-source intelligence
Open source intelligence refers to information gathered from open sources, i.e. information available to the general public. This includes newspaper, the internet, books, phonebooks, scientific journals, radio broadcasts, television, and others.
Since this information is freely available, the difficulty generally lies less in collecting it than in analyzing it.
A major provider of open source intelligence for the US government is the CIA's Foreign Broadcast Information Service, which also makes some of its information available to the public through the World News Connection.