Where do you get this? I've worked in the porn industry for 12 years and have ran porn sites on both Linode AND AWS... They allow it.
That being said, we do things very differently in porn than in the startup world I have come to notice. Most startups scoff PHP, whereas 99% of the porn industry is based on PHP. Not to mention we handle HUGE traffic loads on single servers, and the only time we ever have more than one server (outside of the sites sub 1,000 Alexa) is just for media such as pictures and videos, which are only offloaded to handle as static content while the rest is dynamic.
Only the vocal ones. I find that PHP is used a lot more than what the chatter on HN might lead one to think.
My main problem with PHP is that I'm primarily a Perl dev (but have done some heavy PHP work in the past), and it's syntax is just close enough to make me always aware of how unintuitive it is in comparison, and all the extra steps I have to take to accomplish something simple. It's maddening.
Did you guys use any of the crazy file systems, like MogileFS?