It really confused me that I can't log in to joind.in with my github or twitter/facebook. I just wanted to rate a talk while having 5-minutes break, so it had to be really fast. I didn't have any joind.in account and thought I could create one in a second clicking signin with Github. But there was no error message like you need to Register first filling in a form. It just gave me Login Failed and I thought that website is broken.