Facebook, Yahoo, Flickr and Digg all use non-PHP solutions for the back end. Rails can scale fine once you realize it's not magic; you take a hit from using a

Facebook, Yahoo, Flickr and Digg all use non-PHP solutions for the back end. Rails can scale fine once you realize it's not magic; you take a hit from using a framework designed to make developers happy, not servers, but you can work around it — at the end of the day, Ruby isn't slow like people make it out to be.