This dissertation examines the theory and praxis of taking an expanded concept of the human-computer interface (HCI) and working with the resulting concept to design a writing center website that facilitates online tutoring while fostering a conversational approach for online tutoring sessions. In order to foster a conversational approach, I explore the ways in which interactive digital technologies support the collaborative and communicative nature of online tutoring. I posit that my research will yield a deeper understanding of the visual rhetoric of human-designed computer interfaces in general and writing center online tutoring websites in particular, and will, at the same time, provide support and rationale for the use of interactive digital technologies that utilize the space within the interface to foster a conversational approach to online tutoring, an outcome that the writing center community strongly encourages but acknowledges is difficult to achieve in online tutoring situations (Bell, Harris, Harris and Pemberton, Gillespie and Lerner, Hobson, Monroe, Rickley, Thomas et. al). The resulting prototype design that I submit as part of this dissertation was developed by considering the surface and conceptual dimensions of the HCI along with pedagogies that support interactivity, exploration, communication, collaboration, and community.