Or "facebook uses it". That one tends to go far.

Didn't they start with it and migrate away?

They use something called HHVM, which is a PHP compiler.

http://hhvm.com/

And Hack, their language for HHVM that's basically "static types bolted on to PHP".

http://hacklang.org

An aptly named language if there ever was one.

Hack is more than that. Hack solves every little stupid mistake PHP has as a language. It is a good language developed by smart people, has rules to avoid pitfalls and rules to make things more certain. It retains only the syntax of PHP, but in strict mode, hack can be compared to any other good language.

Aren't C# devs at least as easy to find as php devs already? This would vary regionally I suppose. I'd worry about the future availability of php devs if node/.NET keep growing as open source web backend platforms.

And .NET is as free as php?

Not in places where wages are low.

Cheap for employers is what i'm hearing, but isn't really an incentive for an employee..

It is for employees in countries where there are few or no alternatives.