Unlike weak AI, strong AI observes its environment and gathers experience. It makes its own conclusions, adapts its behavior accordingly, and can express emotions and have values.
For now, strong AI remains a utopian aspiration, closer to science fiction than reality. However, imagining this kind of AI raises questions of several varieties: philosophic and social (what would happen to humans if strong AI came about?), legal (what official status would this AI have?), and economic (would this bring about any upheaval?).