Unlike formal published writing, internet writing—blogs, texts, email—is informal and unfiltered. It expresses more of a writer’s real feelings than does the carefully scrubbed verbiage of a book or magazine.

Speech can be informal and revealing, but it’s a nightmare to analyze: It takes about an hour for a linguist to parse a single minute of speech. Studying handwritten letters isn’t much easier, and the information they provide about how people communicate can be decades or centuries out of date. Internet writing is fresh; it’s easy to work with; its patterns resemble conversations, with their spontaneity and frankness.

A keysmash—a lot of random keys struck at once to express intense feelings—also reveals the typing skill level of the writer (more mid-row letters struck signify the “home keys” where skilled typist’s hands rest) and whether they’re using the typical QWERTY keyboard, a Dvorak one, or a smartphone.

People reveal unconscious patterns even when typing something apparently random, like a keysmash. These appear everywhere in internet writing; the author searches for them; the book’s purpose is to reveal them.

Short words like “of” are common and versatile but carry less information than rarer, longer words like “rhinoceros.