The big downside of this otherwise marvellous website is that the only way to log in is to let Gigya (evil tracking company) track the users. People who are cautious about internet security are therefore having loads of trouble logging in because we need to temporarily disable our defences.
Other websites using login through social networks still work if the user has protection, so I suggest this one is made to work too.
How to do it? As far as I can make out, the actual login buttons are implemented into this website externally (or am I wrong?). If the buttons were part of this website there wouldn't be any trouble with the security software and people could still log in through social networks.