Thrun, a German-born and largely self-taught expert in robotics, is famous for leading the team that built Google’s self-driving car. He is offering his “Introduction to Artificial Intelligence” course online and free of charge. His remote students will get the same lectures as students paying $50,000 a year, the same assignments, the same exams and, if they pass, a “statement of accomplishment” (though not Stanford credit). When The Times wrote about this last month, 58,000 students had signed up for the course. After the article, enrollment leapt to 130,000, from across the globe.