Medium for Textbook Writing

I agree with this post, and I myself have started putting together my lecture notes on Environmental Health for a class I teach now on Medium. While I have not used many multimedia/advanced features, over time I will. If you are interested, take a look at the evolving text here:
https://medium.com/environmental-health

I also think that Medium is a great place for scholarly commnication, and particularly great for hosting journals.