Facebook by 2010 had migrated from college dorm novelty to genuine social infrastructure — the place where extended family reconnected, old friends resurfaced, and professional acquaintances observed each other in contexts that previous generations of human interaction had never created. This compression of social spheres, exciting when it first emerged, was producing a new category of problem: the wrong thing said to the wrong audience.

A few categories of Facebook behavior had emerged as reliably hazardous by the time the platform approached 500 million users:

Political pronouncements to mixed audiences. Posting a strong political opinion to a feed that includes your employer, your clients, your grandmother, and your college roommates is an exercise in guaranteed alienation. The people who agree will approve silently; the people who disagree will remember.

Relationship drama in real time. Vague-posting ("some people just can't be trusted") or explicit argument-airing generates embarrassing digital archaeology that every future romantic interest will eventually find.

Complaints about your employer. Multiple people had been fired by 2010 for Facebook posts critical of their workplaces or managers — documented in enough cases to make this a genuinely well-established risk.

Medical oversharing. Detailed accounts of symptoms, procedures, and diagnoses belong in private messages to close friends, not broadcast to 400 acquaintances.

Photos that contradict your professional persona. The photos were always there; now everyone could see them simultaneously.

The deeper issue was structural: Facebook's design encouraged people to post to a single feed while imagining they were speaking to a specific subset of it. The solution — thinking carefully before posting about who exactly could see it — required habits of digital discretion that took years to develop across the culture.