When signing up, on it asks you to choose a username, password, etc. and read the terms of service.
The terms of service say to choose one's display name carefully. because it can't be changed.
A thread discussing display names makes clear that they are separate things:
I don't ever remember being able to choose my display name, only the username. I want to be able to choose my display name but I'm not seeing how to (I just want my username with the first letter capitalized, i.e. "Prairie").
Thanks for any insight on this.