"Operations Security (OPSEC) is the process of identifying critical information to determine if friendly actions can be observed by adversaries, find if that information could be interpreted to be useful by them and execute measures to eliminate or reduce exploitation."
It is essential to identify and protect little pieces of innocuous data, which could be grouped together to give bigger and meaningful picture. This way of securing information is not just against hackers or corporate espionage but also from unfriendly eyes, social engineering, prying governments and mass surveillance.
OPSEC is not new line of security, it certainly is uncommon & challenging. Secure your data against real but elusive adversaries and not template threats or overrated risks.