well we could talk about it! No particular reason, we're not developers/designers by trade, we have a generalist engineering background and we wanted to do a startup so we just went with what was buzzing at the time and learned everything from almost scratch. (could definitely be that it wasn't the smartest technical choices but since we've been handling the HN spike on our 20$/month linode VPS pretty handsomely so far we must be doing something right)
Any particular reason you guys went with Express/Mongo?