PHP is popular because of low barrier to deploy. All hosting providers offer PHP, while with other technologies you'll have to shop a little.
From the article:
| Rasmus represents what most non-PHP developers hate about PHP.
| Rasmus generally promotes abstention from using frameworks, and the use of PHP as more of a templating language. To him, this translates to raw speed and scalability (load-wise). To everyone else, this translates to piles of procedural spaghetti code, and unmaintainable projects. For roughly 10 years following the birth of PHP in 1995, this was how PHP projects were written.
Also it's worth noting that if you do want to do PHP "right" and use a framework like Zend or Cake you will probably still be shopping around a bit because you're not going to get the ability to use those frameworks out of the box on most hosting providers.
Thats huge.
The thing is that it isn't like say 30% of hosting providers offered it and it slowly got more and more, it was more like massive overnight 100% market penetration.
I've never met a hosting provider that didn't provide it, despite the fact that it is an absolute security nightmare.
I'm still puzzled about the nearly instantaneous and complete market penetration of php.