Threat models – so called “privacy” – can be personal or political.

For example, OpenPGPcan be marginally useful for a small subset of personal threat models, like fiscal fraud, but definitely not for political ones.

A personal threat model, of course, is related to information you want to hide to someone abusing or trying to abuse you – a spouse, a parent, the State, etc.

A political one is related to avoiding a surveillance-based dystopia, recording information about political opponents, etc. Mass surveillance relies on metadata, i.e. not making sense of one's exhaustive profile but comparing their data points to these of everyone else.

The Tor browseris super useful against both threat models, up to and including the State.