The makecode site also contains a wide range of resources including a 14 week introduction to Computer Science. Microsoft also have a UK Digital Skills Programme, a UK STEM eduction site and US Digital Skills Resource site
The Computing At School Forums are a walled-garden community aimed at teachers and other educators. There is a simple sign-up process here, which is free, to become a member. You have to provide some form of independently verifiable means that you are a teacher or an educator, in order to become a member. Searching for 'microbit' or 'micro:bit' within the forum posts brings up results.
Where conversations are relevant to the micro:bit community and with the permission to re-use granted by the author, we have published them in their own Knowledgebase category.