Poder añadir colaboradores al cuaderno. Permitir compartirlo en el mismo formato que Squid cuadernos y así un profesor puede revisarlo a un alumno que se lo envíe y devolverlo para que continúe trabajando en él

Compartilhar caderno com outro usuário, dando opção de ALT ou não os dados

I teach students remotely. It would be really useful if both of us could write on the same page from our respective locations. Right now, the student has to just tell me what to write, then they can see it on screen share (Zoom). This is not as good for teaching as having the ability for both of us to write, since speaking and writing are different cognitive modes.

I want to be able to give long distance lessons to my students

Yes please! The main reason we still prefer Keep oftentimes is online and continuous collaboration. I.e. my collaborators could see me working on a note in real time (wherever they are), which could be achieved with Hangouts but is not as convenient. However, Keep also enables us to work on the note _after_ an online session without having to manually export and later markup PDFs. It is much easier to work on a "living" document (think Google Docs) than on a point-in-time version that constantly gets our of sync between collaborators and introduces additional friction in the use of this app.

Ideal would being able to share to another squid in realtime (like casting to another screen). This way would be sharing the same board with co-workers

If multi-user can write/note/draw something together on their own device...

If the feature can work in cloud-based something...

If the feature can run in local-network such as in a same WiFi-
zone(class-room, meeting-room)

If the feature can operate on web browser like Chrome or Internet-explorer(HTML5)

Imagine how useful could be to work with others, cooperating and getting better results.

That could be the greatest improvement in this app. This is certainly going to make me and others pay for it.

it should be great if you could allow "multiple users" on a single note.

logic:
i create a note. I am the master
i allow others to "join" my note
i allow others to view/edit that note in "real time"

this would allow for "multiple" users to join a session and collaborate in real time.