If you look at the http headers you'll see that they use varnish to cache the content and nginx as webservers. They probably have a pretty decent CDN to deliver

If you look at the http headers you'll see that they use varnish to cache the content and nginx as webservers. They probably have a pretty decent CDN to deliver the content to users across the world. Side-note: I also heard that the founders of Akamai started up after seeing how the porn industry handled all the traffic from geographical different places.