Topics for an article on secrecy
Animals generally endeavor to conceal the location of their den or nest from predators.
Governments and corporations often attempt to conceal information about their operations from other governments.
Preservation of secrets in one of the goals of information security.
Secret keys are essential in most cryptography, which in turn has as its goal the hiding of secrets.
Information hiding is a design principle in much software engineering.
Keeping one's strategy secret is important in many aspects of game theory
Secret societies -- why keep membership a secret? why not?
Bruce Schneier, Secrets and Lies