Thanks for the comment, we added an intro to this blog post:
> For those who don't know Flat (https://flat.io), welcome and here is a quick recap for you. We launched our startup on January 2015. We developed a collaborative platform for composing and editing music scores. Our product is designed for musicians from all around the world, but also for music teachers who can use it with their classes. We aim at changing the way you can learn, teach and make music today. Our answer is Flat and this is the story of the release of the 8th version of our platform.
Indeed, our signup link in the header + fixed to the our auth page, we will change it to our homepage :) Thanks for the feedback for the back to school, we will check that.
We will update them in next few days / weeks to be more precise about private and non-shared content. This actually more apply to public content (e.g. you can see on "popular" pages).
We use Node.js / Lua / Python, depending which services. For example for the engraving part we use some common code shared between the frontend/backend, same for the audio rendering.
Definitely, we already provide a transparent "fork" feature for teachers. With that they can easily distribute copies of their own documents to all their students.
@gnud Thanks for the link, we will fix this shortly. This part of the ToS applies to the public & shared content that can be accessible by everyone on the internet ;-)