When people think about keeping something private, they think about its content: the substance of what was said, done, or arranged. They protect the content, and consider the matter handled. But content is only one part of what an action leaves behind. The other part is its pattern, and the pattern is often revealing in its own right.

Every action generates a record not only of what it was but of its shape: when it happened, where, how often, in what sequence, and between which parties. This record can survive even when the content does not. It is possible to know nothing of what passed between two people and still know that they were in contact, when, how regularly, and how that pattern changed over time.

Read carefully, a pattern of this kind describes a great deal. The rhythm of a person's activity suggests their routine. A change in the rhythm suggests that something itself has changed. The pairing of one party with another, repeated, establishes a relationship without a word of its content being known. The shape of activity is, in effect, a portrait drawn without the subject's features but with their posture intact.

For a person who has been careful with the substance of their affairs, this is the exposure most easily overlooked. They have protected what was said, and assume that protects them. But the fact that something was done, with whom, and when, can place a person, connect them, and reveal the structure of their affairs, even with the content sealed.

An honest assessment of exposure therefore looks past content. It asks not only what could be read but what the pattern of a person's activity, on its own, already shows.

Often it shows more than the person would expect, and more than they have done anything to conceal.