You're logged onto a cloud instance working on a problem with your
fellow devs, and you want to invite them to log in and take a look
at these crazy log messages. What to do?

Oh. You have to ask them to cat their public SSH key, paste it into
IRC (wait, no, it's id_rsa.pub, not id_rsa silly!) then you copy it
and cat it to the end of authorized_hosts.

That's where ssh-import-id comes in. With ssh-import-id, you can add
the public SSH keys from a known, trusted online identity to grant
SSH access.

Currently supported identities include Github and Launchpad.