Another nice little "hidden" thing is that you can get people's public keys from just a GitHub username, and be kind of sure it is keys in active use, by doing

Another nice little "hidden" thing is that you can get people's public keys from just a GitHub username, and be kind of sure it is keys in active use, by doing http://github.com/$username.keys http://github.com/$username.keys. Adding access to a new user? `curl https://github.com/embedding-shapes.keys https://github.com/embedding-shapes.keys >> /home/user/.ssh/authorized_keys`