They cared more about cost and time to market than performance and technical prowess, and in a business context, that is often a correct trade-off.
I don't like it because I prefer small fast clean applications, but I know I'm in the minority and I accept that that's how the business world works.
Cool when you are starting up and all, but surely they must have a bit more money now, and would be able to do it right?
If Facebook with its billions decided it was cheaper to rewrite PHP, the cost/benefit analysis must favor optimizing current code than doing a rewrite
If your users pay you either way, the cheaper option (from a business point of view) is better.
Web-scale? What's web scale? why does my desktop client need to be "web-scale"?
http://engineering.wayfair.com/2013/04/devnull-vs-mongodb-be...