If anyone is interested seeing another interesting service, our organization is currently developing user onboarding over SSH (WIP). All sources are public [1] and easy to follow/read. It's written in nodejs and has nice blessed/blessed-contrib based UI.
The hashbang people are doing a LOT of interesting things. What's nice is that they aren't waiting to get the whole internet onboard with their ideas, they are building the services now.
The best part is that (theoretically), you could install their software on a machine of your own and it would then be capable of providing services to their users.
[1] https://github.com/hashbang/signup-ssh