When launching your online courses, what feature do you consider a must?

That's a good question. I suppose if we looked at all market segments, verticals, and geographies that the most common denominator would be to have an Authoring tool (even if a basic markdown editor), a system of record (to keep track of courses, lessons, users, etc), and a basic invite/registration flow. Nice to have features for the market in general may be must haves for certain markets. For example, if the company is focused on Enterprise sales, the product may need to support SSO with SAML and the like, whereas a solution that focuses on selling to Instructors (individuals and training agencies) may need a set of features that helps them monetize their knowledge. To be honest the must have feature(s) for any solution to host courses successfully would have to have a seamless, easy-to-onboard, and well documented user interface. If that doesn't exist then nothing works ;-).

An effective online course platform should have several key features. Firstly, it should provide a user-friendly interface that is easy to navigate. It should also be responsive and mobile-friendly, allowing to access the course content from any device. Secondly, it should have tools to support communication and collaboration between instructors and students, such as discussion forums, live chat, and video conferencing. Also, the platform should provide analytics and reporting features to track progress, engagement, and performance, allowing to make data-driven decisions to improve the course. I've already tried platforms like Coursera, Kwiga, and Udemy. I have even written reviews about them.