Humbly is not completely anonymous because it will be out of control since no one will take responsibility of their words. Teacher is very important in Humbly because they can see all the senders' name. On the other hands, students know their name is not displayed in front of other students so that they can freely express their feelings.
Here is the student's view that students only see the senders' name if the senders are teacher:
Here is the teacher's view that teacher can see all the senders' name: