The fact that its hosted at Modulus (the guys behind Demeteorizer, which allows you to host meteor apps on Node.js services) would indicate that its almost certainly a Meteor app to me.

I DO think that Meteor is fucking awesome, due to the sheer speed you can crank out commonly requested features (you can add a Google/Facebook/Github Oauth login widget with one line of code), but it sure as hell doesn't seem to scale well these days.