This paper investigates how students evaluate online video for use in assignment work, in order to understand digital literacy with online video in practice. Students sourced content for a written assignment using a customised video retrieval system (VRS), and reflected on their choice of videos. The study examines the key areas influencing the use and evaluation of online video for assignments such as digital literacy, the learning value of video, strategies for integrating video, and the key features of VRSs. This paper examines students' experiences using online video for assignment work and pays particular attention to their evolution of video content and their reasons for selecting videos. Findings show that students select video based on its relevance to their existing knowledge, ability to develop their arguments, and on the source and quality of content. Students display key elements of digital literacy when provided with an authentic task, and the appropriate tools and content to accomplish this. The work also presents a series of recommendations and considerations for future work in the area.