Tech titans are tumbling, US firms are scrambling and a new name in AI has emerged: DeepSeek. This is a Chinese artificial intelligence firm that launched a new chatbot just a month ago. This week - for the second week in a row - it is North America's most downloaded app. But what does this all mean for you? What can DeepSeek do? Data scientist Nikita Roy and computer science professor Maura Grossman take our questions.