Usernames register themselves

Usernames don't need a separate sign-up. The first time any node names a username in an event, it is registered and kept unique, and each later sighting is attached to that same identity.

Asembla reads any one of these fields: username, user, user_name, handle, agent, agent_name, actor, sender, author, owner.

• @flow and flow mean the same name.
• For an email address, the part before the @ is used.
• Names are lowercased. Letters, numbers, dots, dashes and underscores are kept.