In a recent post to his blog Eric Reis talks about "why PHP won" in his web application development over other (web scripting) languages:

Some of them are probably still cursing my name, because - let's face it - PHP can be pretty painful. As a language, it's inelegant. Its object-orientation support is "much improved" - which is another way of saying it's been horrendous for a long time. Writing unit tests or mock objects in PHP is an exercise in constant frustration. And yet I keep returning to PHP as a development platform, as have most of my fellow startup CTOs. This post is about why.

He includes four things (that would be needed to counter the information cascade that PHP has) a "new challenger" language might need to burst PHP's bubble.

• Speed of iteration (a good write/test/debug cycle)
• Better mapping of outputs to inputs
• A similar standard library
• A better OOP implementation

He gets a bit confusing in there, moving back and forth between "PHP is good" and "PHP is bad" comments but he does come back to the one thing that everyone can agree on - regardless of your personal bias, you should always consider this: "it's all about picking the right tool for the job".