For an instructor who is teaching a massive open online course (MOOC), what is the best way to understand their class? What is the best way to view how the students are interacting with the content while the course is running? To help prepare for the next iteration, how should the course's data be best analyzed after the fact? How do these instructional monitoring needs differ between online courses with tens of thousands of students and courses with only tens? This paper reports the results of a survey of 92 MOOC instructors who answered questions about which information they find useful in their course, with the end goal of creating an information display for MOOC instructors. The main findings are: (i) quantitative data sources such as grades, although useful, are not sufficient; understanding the activity in discussion forums and student surveys was rated useful for all use cases by a large majority of respondents, (ii) chat logs were not seen as useful, (iii) for the most part, the same sources of information were seen as useful as found in surveys of smaller online courses, (iv) mockups of existing and novel visualization techniques were responded to positively for use both while the course is running and for planning a revision of the course, and (v) a wide range of views was expressed about other details.