This lecture explores the rise of online video, focusing on YouTube as a popular platform for expression, data source, and even piracy. It delves into the platform's statistics, cultural impact, generativity, video popularity distributions, and its role as a social network and content-diffusion platform. The lecture also discusses YouTube's copyright infringement issues, including near-duplicate video detection and the Content ID system launched in 2007, allowing copyright owners to manage their content on the platform.