I'd disagree if you say PHP powers about 70% of the web. Web servers (and all other kinds of servers) are not written in PHP neither are protocols that drive the web. Operating systems are not written in it either. These (and many more) are what power the web, not web applications. Your definition of what "powers the web" is remarkablly wrong.
Facebook doesn't use web servers or operating systems written in PHP either, right? So if the language that web applications are written in isn't very important to the overall dependability of web applications, then it stands to reason that Facebook's choice of PHP for their web applications shouldn't be a problem either, right?
I had this question in mind while reading your reply. What point are you trying to make with your comment? For my part I wanted to point out that it's unacceptable to say PHP powers 70% of the web. (Check my previous comment's parent.) It has nothing to do with Facebook. And I didn't allude to your inference that choice of language doesn't affect the overall dependability of web applications.
