We describe the development of the Mechanics ReView and Mechanics Online courses. In the first half of the paper we present the history and operation of these courses. We describe the impact of several features, including the use of frequent and embedded assessment to improve etext reading rates, and multiple explicit levels of homework problem to target students of varying skill levels. In the second half of the paper we give special attention to the most recent versions of the course: an online course in the spring of 2012 oriented toward those seeking a review of introductory mechanics, and one in the summer of that year primarily advertised towards teachers. Comparing and contrasting the two courses shows how changes in the audience, timing, and structure of a course can alter certain outcomes (eg attrition rate, reaction to frustration) while leaving others (eg student opinions of various course components) almost untouched. Especially notable is the improvement in student retention of students who attempted at least part of the second assignment from 44% to 74%, a value typical of elective on-campus courses. The course will be offered again in summer 2013.(http://RELATE. MIT. edu/physicscourse).