|USPS.com utilizing AWS's CDN
Realistically, how do you scale a website of that magnitude, from the git-go, for millions and millions of people? It's beyond difficult, even today.
Gmail controlled growth (scale), when they rolled out in 2004, by giving each user a limited number of invites to share with others.
Facebook controlled growth by only rolling out on college campuses.
Twitter had no way to control growth, in the early years, so their servers were overloaded and frequently went down (aka Fail Whale).
So far, I'm impressed with the form page at USPS for ordering free COVID test kits. For starters, it's nothing more than a simple HTML web form. But, even that can overload servers and interfere with routine usps.com web traffic.
Instead of going to www.usps.com to order free COVID test kits, which is running on a single IPv4 address, users go to special.usps.com which has four separate IPv4 address pointing to CloudFront which is an AWS Content Delivery Network(CDN). That's a very smart way to load balance Internet traffic across multiple servers.