Netiquette is a set of rules for proper online behavior. The core rules include remembering the human on the other side, following the same standards of behavior online as in real life, respecting other people's time and privacy, sharing knowledge to benefit others, controlling flame wars, not taking advantage of power over others, and being forgiving of mistakes since everyone was once a newbie. The rules aim to make online interactions run smoothly and avoid misunderstandings by encouraging empathy, ethics, and consideration of others.