Dr. Koster's primary areas of scholarship are in women’s literacy and literate practices in the later Middle Ages, especially in England, and in applications of social media and digital humanities to pedagogy and English literature. In 2009, she received the Award for Outstanding Scholarly Achievement from the Southeastern Medieval Association; in 2014 she received the award for Outstanding Teaching from that organization. In 2012 she was awarded Winthrop’s Jane LaRoche Graduate Faculty Award and in 2015 was named Winthrop’s Distinguished Professor. She currently is finishing a book on medieval women's literacy, working with issues of material culture in Chaucer and with the development of opus Anglicanum in England. Recently she has collaborated with both colleagues and students in writing about the effects of using social media in the college writing and literature classrooms. She currently serves on the Medieval Studies Committee and the Master of Liberal Arts Advisory Committee, and has held a number of positions in University Governance, including two terms as Chair of Academic Council and three terms as Chair of the Committee on University Curriculum.
Besides a long series of articles, essays, and reviews, she's published a number of poems in small collections. Koster also studies book arts and makes and binds books. All of this serves as a cover for her fanatical interests in Doctor Who, Sherlock Holmes, and NASCAR and as an excuse for making her famous five-chocolate brownies.