Something or someone who, due to sensitivity to his, her, or its surroundings, acts as an indicator and early warning of possible adverse conditions or danger. Refers to the former practice of taking caged canaries into coal mines—the birds would die if methane gas was present, thereby alerting miners to the danger. Wildlife in disaster movies always acts like the miner's canary, fleeing the scene when catastrophe is imminent. John was used as a miner's canary to see the test drug's effects on the human mind.

Something that extracts or gathers data from a computer. "Spyware" is a malicious type of data miner. IT is going to use a data miner to get us that information. I bet Ben put a data miner on my computer to spy on me!

Malicious software designed to surreptitiously record and transmit a computer user's private information to someone or something. The judge ruled that the tech company was installing spyware by virtue of the fact that users were at no point warned that their information was being collected. I've only ever downloaded a movie illegally once, and I ended up with such nasty spyware as a result that I never did it again.