Name is your human-readable name (to be shown on the leaderboard).

ID is used in the URLs for your repos (must be composed of lower-case letters, digits or hyphyns, must start with a lower-case letter).

Password is needed when Persona is closed.

SSH public key is needed if you want to access repos hosted on Gonito.net (usually it is .ssh/id_rsa.pub in your home directory after you generated private/public key pair).

ID cannot be changed once it is set up.

You don't need to specify your ID and SSH public key, if you don't use private repos hosted on Gonito.net.