There are major federal government websites that have office hours. The EIN application website only works between 9am and 5pm. I like to imagine that it's this way because there's no webapp, there's just a team of people who get all the HTTP requests and manually respond to them. This would also explain its speed.
MOLOCH.
https://slatestarcodex.com/2014/07/30/meditations-on-moloch/