Pinwale is the code name for an NSA database of archived foreign and domestic emails it has collected under its SIGINT

SIGINT

Signals intelligence is intelligence-gathering by interception of signals, whether between people , whether involving electronic signals not directly used in communication , or combinations of the two...

 (Signals Intelligence) efforts. This database of communications intercepts includes the personal correspondence of former President Bill Clinton.

Its existence was revealed by an NSA analyst who was trained to use it during 2005.