Kanban is an agile method that uses a visual board with columns to manage work in progress. It focuses on limiting work-in-progress instead of having sprints or deadlines. Kanban can be better than Scrum for small teams, startups, or when tasks are variable since it allows for faster feature deployment without fixed timeboxes and less process overhead. The key aspects of Kanban include a customizable board with columns, optional constraints on work-in-progress per column, and an optional expedite row to prioritize certain tasks.